A photolithography alignment structure and a method of manufacturing the same

Abstract

The application provides a photolithography alignment structure and a manufacturing method thereof. The structure comprises a first partial substrate and a second partial substrate; the thickness of the first partial substrate is not equal to the thickness of the second partial substrate; a hard mask coating layer is arranged on one side of the first partial substrate; the orthographic projection of the hard mask coating layer on the first partial substrate is truly contained in the first partial substrate. In the application, a ternary photolithography alignment structure is arranged. Compared with a traditional binary photolithography alignment structure, the diffraction effect and the diffraction quality are improved, the sensitivity of size fine adjustment and detection light change is reduced, the diffraction light signal intensity and quality are better, the robustness of the structure and the process change is better, and the influence of phase cancellation of binary materials due to the thickness of certain materials is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor technology, and in particular to a photolithography alignment structure and a manufacturing method thereof. BACKGROUND

[0002] In the manufacturing process of a semiconductor device, photolithography is an important process step, which copies a designed pattern onto a wafer through a photoresist by coating the photoresist and exposing light. In the photolithography process, alignment is usually performed by setting alignment marks on the wafer.

[0003] A conventional photolithography alignment structure generally adopts a binary structure, for example, an alignment structure formed by etching a structure of a certain depth on a silicon surface. However, the conventional alignment mark does not consider alignment mark structures with a phase difference of 3 or more, and the diffraction effect and diffraction quality are not good.

[0004] Therefore, how to improve the diffraction effect and diffraction quality of the photolithography alignment structure is a technical problem to be solved in the field. SUMMARY

[0005] In view of this, this summary section is provided to introduce the concepts in a simplified form, which will be described in detail in the following detailed description section. This summary section is not intended to identify key or essential features of the claimed technical solution, nor is it intended to limit the scope of the claimed technical solution.

[0006] The purpose of the present application is to provide a photolithography alignment structure and a manufacturing method thereof, which can improve the diffraction effect and diffraction quality of the photolithography alignment structure.

[0007] To achieve the above-mentioned purpose, the present application has the following technical solutions:

[0008] In a first aspect, the embodiments of the present application provide a photolithography alignment structure, comprising:

[0009] a first portion of a substrate and a second portion of a substrate;

[0010] a thickness of the first portion of the substrate is not equal to a thickness of the second portion of the substrate;

[0011] a hard mask coating layer located on one side of the first portion of the substrate; the hard mask coating layer is contained in the first portion of the substrate in orthographic projection.

[0012] In a possible implementation, the first portion of the substrate, the second portion of the substrate, and the hard mask coating layer are in an axial symmetric structure.

[0013] In a possible implementation, the equivalent phase of the region of the first partial substrate other than the hard mask coating region is 2 / 3pi, the equivalent phase of the second partial substrate region is 0, and the equivalent phase of the hard mask coating region is -2 / 3pi.

[0014] The equivalent phase of the structure has a phase shift or a symmetric change feature based on the above equivalent phase.

[0015] The region of the first partial substrate other than the hard mask coating region is divided into four parts, and each part accounts for 1 / 15 of the total width of the lithography alignment structure; the four parts are arranged at intervals;

[0016] The second partial substrate region is divided into two parts, and each part accounts for 1 / 5 of the total width of the lithography alignment structure; the two parts are arranged at intervals;

[0017] The hard mask coating region accounts for 1 / 3 of the total width of the lithography alignment structure.

[0018] In a possible implementation, the equivalent phase of the region of the first partial substrate other than the hard mask coating region is 2 / 3pi, the equivalent phase of the second partial substrate region is 0, and the equivalent phase of the hard mask coating region is -2 / 3pi.

[0019] The region of the first partial substrate other than the hard mask coating region is divided into two parts, and each part accounts for 2 / 15 of the total width of the lithography alignment structure; the two parts are arranged at intervals;

[0020] The second partial substrate region is divided into three parts, and each part accounts for 2 / 15 of the total width of the lithography alignment structure; the three parts are arranged at intervals;

[0021] The hard mask coating region is divided into two parts, and each part accounts for 1 / 6 of the total width of the lithography alignment structure.

[0022] In a possible implementation, the equivalent phase of the region of the first partial substrate other than the hard mask coating region is 2 / 3pi, the equivalent phase of the second partial substrate region is -2 / 3pi, and the equivalent phase of the hard mask coating region is 0.

[0023] The region of the first partial substrate other than the hard mask coating region is divided into four parts, two of which account for 2 / 15 of the total width of the lithography alignment structure, and the other two account for 1 / 15 of the total width of the lithography alignment structure; the four parts are arranged at intervals;

[0024] The second part of the substrate region is divided into two parts, each part accounting for 1 / 5 of the total width of the lithography alignment structure; the two parts are arranged with an interval;

[0025] The hard mask coating region accounts for 1 / 5 of the total width of the lithography alignment structure.

[0026] In a possible implementation, the equivalent phase of the region of the first part of the substrate except the hard mask coating region is 2 / 3π, the equivalent phase of the second part of the substrate region is 0, and the equivalent phase of the hard mask coating region is -2 / 3π;

[0027] The region of the first part of the substrate except the hard mask coating region is divided into four parts, two of which account for 2 / 15 of the total width of the lithography alignment structure, and the other two account for 1 / 15 of the total width of the lithography alignment structure;

[0028] The second part of the substrate region is divided into four parts, each part accounting for 1 / 15 of the total width of the lithography alignment structure; the four parts are arranged with an interval;

[0029] The hard mask coating region accounts for 1 / 3 of the total width of the lithography alignment structure.

[0030] In a possible implementation, the equivalent phase of the region of the first part of the substrate except the hard mask coating region is 2 / 3π, the equivalent phase of the second part of the substrate region is 0, and the equivalent phase of the hard mask coating region is -2 / 3π;

[0031] The region of the first part of the substrate except the hard mask coating region is divided into four parts, two of which account for 2 / 15 of the total width of the lithography alignment structure, and the other two account for 1 / 15 of the total width of the lithography alignment structure; the four parts are arranged with an interval;

[0032] The second part of the substrate region is divided into two parts, each part accounting for 2 / 15 of the total width of the lithography alignment structure; the two parts are arranged with an interval;

[0033] The hard mask coating region is divided into five parts, each part accounting for 1 / 15 of the total width of the lithography alignment structure.

[0034] In a second aspect, the embodiments of the present application provide a manufacturing method of a lithography alignment structure, comprising:

[0035] providing an initial substrate;

[0036] depositing a hard mask coating on one side of the initial substrate;

[0037] depositing a photoresist coating on a side of the hard mask coating distal from the original substrate; the original substrate covered with the photoresist coating as a first partial substrate, the region of the original substrate not covered with the photoresist coating as a second partial substrate region;

[0038] lithographically and etching away the hard mask coating and part of the original substrate of the second partial substrate region to form the second partial substrate;

[0039] laterally etching the photoresist coating to expose part of the hard mask coating;

[0040] etching the exposed hard mask coating; the hard mask coating being a true superset of the first partial substrate in orthographic projection;

[0041] removing the photoresist coating.

[0042] In one possible implementation, the hard mask coating comprises a stack of one or more materials.

[0043] In one possible implementation, the photoresist coating comprises a photoresist, or a combined stack of a photoresist and an antireflective coating.

[0044] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0045] The embodiments of the present application provide a lithography alignment structure and a manufacturing method thereof, the structure comprising: a first partial substrate and a second partial substrate; the thickness of the first partial substrate not equaling the thickness of the second partial substrate; a hard mask coating located on a side of the first partial substrate; the hard mask coating being a true superset of the first partial substrate in orthographic projection. Thus, a ternary lithography alignment structure is provided in the present application, compared with the traditional binary lithography alignment structure, the diffraction effect and quality are improved, the sensitivity of size fine-tuning and detection light change is reduced, so that the diffraction light signal intensity and quality are both good, that is, the robustness to structure and process change is better, and the influence of phase cancellation of binary materials due to the thickness of certain material is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0047] The above and other features, advantages, and aspects of embodiments of the present disclosure will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings. The same or similar components have the same or similar reference labels. It should be understood that the drawings are not necessarily to scale, with emphasis instead being placed upon illustrating the principles of the embodiments.

[0048] Figure 1 A schematic diagram of a ternary photolithography alignment structure is shown;

[0049] Figure 2 A schematic diagram of another photolithography alignment structure is shown;

[0050] Figure 3 A reference diagram of the equivalent phase of each part of S3-1 is shown;

[0051] Figure 4 A schematic diagram of another photolithography alignment structure is shown;

[0052] Figure 5 A schematic diagram of another photolithography alignment structure is shown;

[0053] Figure 6 A schematic diagram of another photolithography alignment structure is shown;

[0054] Figure 7 A schematic diagram of another photolithography alignment structure is shown;

[0055] Figure 8 A flowchart of a manufacturing method of a photolithography alignment structure is shown;

[0056] Figure 9 A schematic diagram of a structure in a manufacturing process of a photolithography alignment structure is shown;

[0057] Figure 10 A schematic diagram of a structure in a manufacturing process of another photolithography alignment structure is shown;

[0058] Figure 11 A schematic diagram of a structure in a manufacturing process of another photolithography alignment structure is shown;

[0059] Figure 12 A schematic diagram of a structure in a manufacturing process of another photolithography alignment structure is shown. DETAILED DESCRIPTION

[0060] In order to make the above objectives, characteristics and advantages of the present application more apparent, concrete embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0061] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced without the specific details. In other instances, well-known methods have not been described in detail in order not to unnecessarily obscure aspects of the present application.

[0062] As described in the background, the applicant has found that, in the manufacturing process of semiconductor devices, photolithography is an important process step, which copies the designed pattern onto the wafer through photoresist by coating photoresist and exposure. In the photolithography process, alignment is usually performed by setting alignment marks on the wafer.

[0063] The conventional photolithography alignment structure generally adopts a binary structure, for example, an alignment structure formed by etching a structure on the silicon surface to a certain depth. However, the conventional mark does not consider the mark structure with a phase difference of 3 or more, and the diffraction effect and diffraction quality are not good.

[0064] For example, for the alignment behavior after the sidewall deposition process, the conventional method defaults some improvements on the ideal structure and does not conduct in-depth research. The conventional diffraction mark structure mainly adopts diffraction-based alignment marks, including a grating structure with a 16-micron duty cycle of 1:1, an AH32 structure (equally dividing a mark in the grating structure into 3 parts), an AH53 structure (equally dividing the mark position in the grating structure into 5 parts), and an AH74 structure (equally dividing the mark in the grating structure into 7 parts). The optimal structure of the conventional mark defaults that the mark has a π phase difference, so that the best diffraction efficiency can be obtained. However, the conventional mark does not consider the mark structure with a phase difference of 3 or more.

[0065] Therefore, how to improve the diffraction effect and diffraction quality of the photolithography alignment structure is a technical problem to be solved in the field.

[0066] To solve the above technical problems, the embodiment of the present application provides a photolithography alignment structure and a manufacturing method thereof, the structure comprising: a first partial substrate and a second partial substrate; the thickness of the first partial substrate is not equal to the thickness of the second partial substrate; a hard mask coating layer is located on one side of the first partial substrate; the orthogonal projection of the hard mask coating layer on the first partial substrate is truly contained in the first partial substrate. Thus, in the present application, a ternary photolithography alignment structure is provided, compared with the traditional binary photolithography alignment structure, the diffraction effect and the diffraction quality are improved, the sensitivity to size adjustment and detection light change is reduced, so that the diffraction light signal intensity and quality are both good, that is, the robustness to structure and process change is better, and the influence of phase cancellation of binary materials due to the thickness of certain materials is reduced.

[0067] Exemplary structure

[0068] Referring to Figure 1 Fig. 1 is a schematic diagram of a ternary photolithography alignment structure provided by the embodiment of the present application, comprising:

[0069] a first partial substrate 1 and a second partial substrate 2;

[0070] the thickness of the first partial substrate 1 is not equal to the thickness of the second partial substrate 2;

[0071] a hard mask coating layer 3 is located on one side of the first partial substrate 1; the orthogonal projection of the hard mask coating layer 3 on the first partial substrate 1 is truly contained in the first partial substrate 1.

[0072] Thus, in the embodiment of the present application, a ternary photolithography alignment structure is provided, compared with the traditional binary photolithography alignment structure, the diffraction effect and the diffraction quality are improved, the sensitivity to size adjustment and detection light change is reduced, so that the diffraction light signal intensity and quality are both good, that is, the robustness to structure and process change is better, and the influence of phase cancellation of binary materials due to the thickness of certain materials is reduced.

[0073] Specifically, in a possible implementation manner, in order to facilitate photolithography alignment and improve the accuracy of photolithography alignment, the first partial substrate 1, the second partial substrate 2 and the hard mask coating layer 3 provided by the embodiment of the present application are in an axial symmetric structure.

[0074] In a possible implementation manner, referring to Figure 2 Fig. 2 is a schematic diagram of another photolithography alignment structure provided by the embodiment of the present application, the equivalent phase of the region of the first partial substrate 1 except the region of the hard mask coating layer 3 is 2 / 3π, the equivalent phase of the region of the second partial substrate 2 is 0, and the equivalent phase of the region of the hard mask coating layer 3 is -2 / 3π;

[0075] The region of the first substrate 1 except the region of the hard mask coating 3 is divided into four parts 101, 102, 103 and 104, and each part accounts for 1 / 15 of the total width of the lithography alignment structure; the four parts are arranged at intervals;

[0076] The region of the second substrate 2 is divided into two parts 201 and 202, and each part accounts for 1 / 5 of the total width of the lithography alignment structure; the two parts are arranged at intervals;

[0077] The region of the hard mask coating 3 only has one part 301, which accounts for 1 / 3 of the total width of the lithography alignment structure.

[0078] Specifically, referring to Figure 2 As shown in the figure, the phase relationship and size of S3-1 meet: the structures are 101, 201, 103, 301, 104, 202 and 102 in sequence. Among them, the equivalent phase of the 101 region is 2 / 3π, and the width is 1 / 15*period; the equivalent phase of the 201 region is 0, and the width is 1 / 5*period; the equivalent phase of the 103 region is 2 / 3π, and the width is 1 / 15*period; the equivalent phase of the 301 region is -2 / 3π, and the width is 1 / 3*period; the equivalent phase of the 104 region is 2 / 3π, and the width is 1 / 15*period; the equivalent phase of the 202 region is 0, and the width is 1 / 5*period; the equivalent phase of the 102 region is 2 / 3π, and the width is 1 / 15*period. S3-1 is a symmetric structure.

[0079] Referring to Figure 3 As shown in the figure, it is a reference diagram of the equivalent phase of each part of S3-1 provided by the embodiment of the application, parallel light is incident on the structure surface, and the phase difference at any height of the parallel surface is 2 / 3*π, 0 and -2 / 3*π respectively.

[0080] In a possible implementation, referring to Figure 4 As shown in the figure, it is a schematic diagram of another lithography alignment structure provided by the embodiment of the application, the equivalent phase of the region of the first substrate 1 except the region of the hard mask coating 3 is 2 / 3π, the equivalent phase of the region of the second substrate 2 is 0, and the equivalent phase of the region of the hard mask coating 3 is -2 / 3π;

[0081] The region of the first substrate 1 except the region of the hard mask coating 3 is divided into two parts 101 and 102, and each part accounts for 2 / 15 of the total width of the lithography alignment structure; the two parts are arranged at intervals;

[0082] The region of the second substrate 2 is divided into three parts 201, 202 and 203, and each part accounts for 2 / 15 of the total width of the lithography alignment structure; the three parts are arranged at intervals;

[0083] The hard mask coating layer 3 region is divided into two parts 301 and 302, and each part accounts for 1 / 6 of the total width of the photolithography alignment structure.

[0084] Specifically, referring to FIG. 3B, the phase relationship and size of S3-2 satisfy: the structures are 101, 201, 301, 203, 302, 202, and 102 in sequence. Figure 4 As shown in FIG. 3B, the equivalent phase of the 101 region is 2 / 3π, and the width is 2 / 15*period; the equivalent phase of the 201 region is 0, and the width is 2 / 15*period; the equivalent phase of the 301 region is -2 / 3π, and the width is 1 / 6*period; the equivalent phase of the 203 region is 0, and the width is 2 / 15*period; the equivalent phase of the 302 region is -2 / 3π, and the width is 16*period; and the equivalent phase of the 102 region is 2 / 3π, and the width is 2 / 15*period. S3-2 is a symmetric structure.

[0085] In a possible implementation, referring to FIG. 4B, which is a schematic diagram of another photolithography alignment structure provided by an embodiment of the present application, the equivalent phase of the region of the first part of the substrate 1 except the hard mask coating layer 3 region is 2 / 3π, the equivalent phase of the second part of the substrate 2 region is -2 / 3π, and the equivalent phase of the hard mask coating layer 3 region is 0. Figure 5

[0086] The region of the first part of the substrate 1 except the hard mask coating layer 3 region is divided into four parts 101, 102, 103, and 104, wherein two parts 103 and 104 account for 2 / 15 of the total width of the photolithography alignment structure respectively, and the other two parts 101 and 102 account for 1 / 15 of the total width of the photolithography alignment structure respectively; and the four parts 101, 102, 103, and 104 are arranged at intervals.

[0087] The second part of the substrate 2 region is divided into two parts 201 and 202, and each part accounts for 1 / 5 of the total width of the photolithography alignment structure; and the two parts 201 and 202 are arranged at intervals.

[0088] The hard mask coating layer 3 region is only one part 301, and accounts for 1 / 5 of the total width of the photolithography alignment structure.

[0089] ​Specifically, the phase relationship and size of S3-3 satisfy: the structure is 101, 201, 103, 301, 104, 202, and 102 in sequence. Wherein, the equivalent phase of the 101 area is 2 / 3π, and the width is 1 / 15*period; the equivalent phase of the 201 area is -2 / 3π, and the width is 1 / 5*period; the equivalent phase of the 103 area is 2 / 3π, and the width is 2 / 15*period; the equivalent phase of the 301 area is 0, and the width is 1 / 5*period; the equivalent phase of the 104 area is 2 / 3π, and the width is 2 / 15*period; the equivalent phase of the 202 area is -2 / 3π, and the width is 1 / 5*period; the equivalent phase of the 102 area is 2 / 3π, and the width is 1 / 15*period. S3-3 is a symmetric structure.

[0090] Meanwhile, in a possible implementation, the application is directed to ternary structure, and a grating alignment structure for simultaneously realizing first-order and fifth-order diffraction light enhancement is invented, including Figure 6 S5-1 structure shown in the figure, Figure 7 S5-2 structure shown in the figure. And the deformation structure of fine adjustment, phase structure symmetry change, shift change based on the structure.

[0091] Referring to Figure 6 Fig. 2 shows another lithography alignment structure provided by the embodiment of the application, that is, the equivalent phase of the area of the first part of the substrate 1 except the area of the hard mask coating layer 3 is 2 / 3π, the equivalent phase of the area of the second part of the substrate 2 is 0, and the equivalent phase of the area of the hard mask coating layer 3 is -2 / 3π;

[0092] The area of the first part of the substrate 1 except the area of the hard mask coating layer 3 is divided into four parts 101, 102, 103, and 104, wherein the proportion of two parts 103 and 104 to the total width of the lithography alignment structure is 2 / 15 respectively, and the proportion of the other two parts 101 and 102 to the total width of the lithography alignment structure is 1 / 15 respectively;

[0093] The area of the second part of the substrate 2 is divided into four parts 201, 202, 203, and 204, and each part accounts for 1 / 15 of the total width of the lithography alignment structure; the four parts 201, 202, 203, and 204 are arranged at intervals;

[0094] The area of the hard mask coating layer 3 has only one part 301, and the proportion of the part 301 to the total width of the lithography alignment structure is 1 / 3.

[0095] That is, in the embodiment of the application, referring to Figure 6The phase relationship and size of S5-1 meet: the structure is 101, 201, 103, 203, 301, 204, 104, 202, 102 in turn. The equivalent phase of the 101 area is 2 / 3π, and the width is 1 / 15*period; the equivalent phase of the 201 area is 0, and the width is 1 / 15*period; the equivalent phase of the 103 area is 2 / 3π, and the width is 2 / 15*period; the equivalent phase of the 203 area is 0, and the width is 1 / 15*period; the equivalent phase of the 301 area is -2 / 3π, and the width is 1 / 3*period; the equivalent phase of the 204 area is 0, and the width is 1 / 15*period; the equivalent phase of the 104 area is 2 / 3π, and the width is 2 / 15*period; the equivalent phase of the 202 area is 0, and the width is 1 / 15*period; the equivalent phase of the 102 area is 2 / 3π, and the width is 1 / 15*period. S5-1 is a symmetrical structure.

[0096] Referring to Figure 7 As shown in FIG. 5, the equivalent phase of the area of the first part of the substrate 1 except the area of the hard mask coating layer 3 is 2 / 3π, the equivalent phase of the area of the second part of the substrate 2 is 0, and the equivalent phase of the area of the hard mask coating layer 3 is -2 / 3π.

[0097] The area of the first part of the substrate 1 except the area of the hard mask coating layer 3 is divided into four parts 101, 102, 103 and 104, wherein the proportion of two parts 103 and 104 to the total width of the lithography alignment structure is 2 / 15 respectively, and the proportion of the other two parts to the total width of the lithography alignment structure is 1 / 15 respectively; the four parts 101, 102, 103 and 104 are arranged at intervals;

[0098] The area of the second part of the substrate 2 is divided into two parts 201 and 202, and each part accounts for 2 / 15 of the total width of the lithography alignment structure; the two parts 201 and 202 are arranged at intervals;

[0099] The area of the hard mask coating layer 3 is divided into five parts 301, 302, 303, 304 and 305, and each part accounts for 1 / 15 of the total width of the lithography alignment structure.

[0100] Specifically, referring to Figure 7As shown, the phase relationship and size of S5-2 satisfy: the structures are 101, 301, 103, 303, 201, 305, 202, 304, 104, 302, and 102 in turn. Among them, the equivalent phase of the 101 region is 2 / 3π, and the width is 1 / 15*period; the equivalent phase of the 301 region is -2 / 3π, and the width is 1 / 15*period; the equivalent phase of the 103 region is 2 / 3π, and the width is 2 / 15*period; the equivalent phase of the 303 region is -2 / 3π, and the width is 1 / 15*period; the equivalent phase of the 201 region is 0, and the width is 2 / 15*period; the equivalent phase of the 305 region is -2 / 3π, and the width is 1 / 15*period; the equivalent phase of the 202 region is 0, and the width is 2 / 15*period; the equivalent phase of the 304 region is -2 / 3π, and the width is 1 / 15*period; the equivalent phase of the 104 region is 2 / 3π, and the width is 2 / 15*period; the equivalent phase of the 302 region is -2 / 3π, and the width is 1 / 15*period; and the equivalent phase of the 102 region is 2 / 3π, and the width is 1 / 15*period. S5-1 is a symmetrical structure.

[0101] The embodiment of the present application provides a photolithography alignment structure, which comprises: a first partial substrate and a second partial substrate; the thickness of the first partial substrate is not equal to the thickness of the second partial substrate; a hard mask coating layer is located on one side of the first partial substrate; and the orthogonal projection of the hard mask coating layer on the first partial substrate is completely contained in the first partial substrate. Thus, a ternary photolithography alignment structure is provided in the present application. Compared with a traditional binary photolithography alignment structure, the diffraction effect and diffraction quality are improved, the sensitivity to size fine adjustment and detection light change is reduced, so that the diffraction light signal intensity and quality are both good, that is, the robustness to structure and process change is better, and the influence of phase cancellation of binary materials due to the thickness of a certain material is reduced.

[0102] It should be noted that the structure provided by the embodiment of the present application and the structure obtained by translation, phase inversion and the like of the structure provided by the embodiment of the present application are all within the protection scope. For the structure provided by the embodiment of the present application, the alignment characteristics of the structure obtained by translation or symmetry of the equivalent phase around 0-2π phase space are still within the protected scope. For example, referring to the structure shown in Figure 2 As shown in the structure, the equivalent phase of the region except the region of the hard mask coating layer 3 in the first partial substrate 1 is 2 / 3π+fixed phase, the equivalent phase of the region of the second partial substrate 2 is 0+fixed phase, and the equivalent phase of the region of the hard mask coating layer 3 is -2 / 3π+fixed phase; or the equivalent phase of the region except the region of the hard mask coating layer 3 in the first partial substrate 1 is -2 / 3π+fixed phase, the equivalent phase of the region of the second partial substrate 2 is 0+fixed phase, and the equivalent phase of the region of the hard mask coating layer 3 is 2 / 3π+fixed phase.

[0103] A slight change in the equivalent phase, for example, within a range of ±1 / 6π, caused by actual process fluctuations, is still within the scope of the present application.

[0104] A slight modification in the structure, including a duty cycle change, addition of a top layer or other deposition of a thin film coating, is within the scope of the present application.

[0105] Exemplary method

[0106] Referring to Figure 8 Fig. 1 shows a flowchart of a method for manufacturing a lithography alignment structure according to an embodiment of the present application, which includes the following steps:

[0107] S101: providing an initial substrate;

[0108] S102: depositing a hard mask coating on one side of the initial substrate;

[0109] S103: depositing a photoresist coating on the side of the hard mask coating away from the initial substrate; the initial substrate covered with the photoresist coating serves as a first partial substrate, and the area of the initial substrate not covered with the photoresist coating serves as a second partial substrate area.

[0110] Referring to Figure 9 Fig. 2 shows a schematic diagram of a structure in the manufacturing process of a lithography alignment structure according to an embodiment of the present application, which provides an initial substrate 11, deposits a hard mask coating 12 on one side of the initial substrate 11, and deposits a photoresist coating 13 on the side of the hard mask coating 12 away from the initial substrate 11; the initial substrate 11 covered with the photoresist coating 13 serves as a first partial substrate 1, and the area of the initial substrate 11 not covered with the photoresist coating 13 serves as a second partial substrate 2 area.

[0111] S104: performing lithography and etching to remove the hard mask coating of the second partial substrate area and part of the initial substrate, to form the second partial substrate.

[0112] Referring to Figure 10 Fig. 3 shows another schematic diagram of a structure in the manufacturing process of a lithography alignment structure according to an embodiment of the present application, in which the hard mask coating 12 of the second partial substrate 2 area and part of the initial substrate 11 can be removed by lithography and etching to form the second partial substrate 2.

[0113] It should be noted that the etching depth is not specifically limited in the present embodiment, and can be set by a person skilled in the art according to the actual situation.

[0114] S105: performing lateral etching on the photoresist coating to expose part of the hard mask coating.

[0115] Referring toFigure 11 The diagram shown is a schematic diagram of the structure in the manufacturing process of another photolithography alignment structure provided in this application embodiment. In this application embodiment, the photoresist coating 13 can be etched laterally to expose part of the hard mask coating 12.

[0116] S106: Etch to expose the hard mask coating; the orthographic projection of the hard mask coating onto the first portion of the substrate is truly contained within the first portion of the substrate.

[0117] See Figure 12 The diagram shown is a schematic diagram of another photolithographic alignment structure manufacturing process provided in this application embodiment. In this application embodiment, the exposed hard mask coating 12 can be etched; the orthographic projection of the hard mask coating 12 onto the first part of the substrate 1 is truly contained in the first part of the substrate 1.

[0118] S107: Remove the photoresist coating.

[0119] See Figure 1 The diagram shown is a schematic diagram of another photolithographic alignment structure provided in the embodiment of this application. In the embodiment of this application, the photoresist coating 13 can be removed to obtain the final ternary photolithographic alignment structure.

[0120] In one possible implementation, the hard mask coating 3 comprises a stack of one or more materials. The materials of the first substrate 1 and the second substrate 2 may include semiconductor materials such as silicon.

[0121] In one possible implementation, the photoresist coating 13 comprises a photoresist, or a combination of a photoresist and an antireflective coating.

[0122] Other processes that can form the ternary alignment structure of the present invention may include: step etching, etching and deposition combined techniques, etc.

[0123] The normalized diffraction efficiencies of the five structures of this invention and commercial binary alignment structures are compared in Table 1 below. AH32 and AH53 are two commercial alignment structures, and WQ0, WQ1, WQ3, WQ5, and WQ7 represent the 0th, 1st, 3rd, 5th, and 7th order normalized diffraction efficiencies, respectively. From the diffraction efficiency perspective, the invented structures exhibit comparable or better diffraction intensities than the corresponding commercial binary structures in the 1st and 3rd order, or the 1st and 5th order.

[0124] Structure WQ0 WQ1 WQ3 WQ5 WQ7 AH32 27.4 25 44.4 1 0.5 S3-1 3.3 44 30.2 2.2 3.8 S3-2 3.2 34.7 42.2 2.2 1 S3-3 9.9 25.9 52.9 0 1.4 AH53 39.6 25 2.7 36 0.5 S5-1 3.3 46 2.8 29.3 1.4 S5-2 3.3 32.5 2.8 42.8 0

[0125] Table 1

[0126] The embodiment of the present application provides a manufacturing method of a photoetching alignment structure, and the structure formed by the method comprises: a first partial substrate and a second partial substrate; the thickness of the first partial substrate is not equal to the thickness of the second partial substrate; a hard mask coating layer is located on one side of the first partial substrate; the orthographic projection of the hard mask coating layer on the first partial substrate is contained in the first partial substrate. Thus, the ternary photoetching alignment structure is arranged in the present application, compared with the traditional binary photoetching alignment structure, the diffraction effect and the diffraction quality are improved, the sensitivity of size fine adjustment and detection light change is reduced, so that the diffraction light signal intensity and quality are better, that is, the robustness to structure and process change is better, and the influence of phase cancellation of binary materials due to the thickness of certain material is reduced.

[0127] Each of the embodiments in the specification is described in a progressive manner, and the same and similar parts of each of the embodiments can be referred to each other, and each of the embodiments mainly describes the difference from other embodiments. Especially, for the method embodiment, since it is basically similar to the structure embodiment, the description is relatively simple, and the related parts can be referred to the part of the method embodiment.

[0128] The above is only the preferred embodiment of the present application, although the present application has disclosed the above preferred embodiment, however, it is not used to limit the present application. Any person skilled in the art, without departing from the scope of the technical scheme of the present application, can make many possible changes and modifications to the technical scheme of the present application by using the disclosed method and technical content, or modify the equivalent embodiment of equivalent change. Therefore, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present application, without departing from the content of the technical scheme of the present application, still belongs to the protection scope of the technical scheme of the present application.

Claims

1. A lithographic alignment structure, characterized by, Comprising: a first partial substrate and a second partial substrate; a thickness of the first partial substrate is not equal to a thickness of the second partial substrate; a hard mask coating layer located on one side of the first partial substrate; the hard mask coating layer is orthographically true contained in the first partial substrate.

2. The structure of claim 1, wherein The first partial substrate, the second partial substrate and the hard mask coating layer are in an axial symmetric structure.

3. The structure according to any one of claims 1-2, wherein An equivalent phase of a region of the first partial substrate except the region of the hard mask coating layer is 2 / 3π, an equivalent phase of a region of the second partial substrate is 0, and an equivalent phase of the region of the hard mask coating layer is -2 / 3π. The equivalent phase includes a phase obtained by phase translation or symmetric change of the equivalent phase. The region of the first partial substrate except the region of the hard mask coating layer is divided into four parts, and each part accounts for 1 / 15 of the total width of the lithography alignment structure; the four parts are arranged with intervals; The region of the second partial substrate is divided into two parts, and each part accounts for 1 / 5 of the total width of the lithography alignment structure; the two parts are arranged with intervals; The region of the hard mask coating layer accounts for 1 / 3 of the total width of the lithography alignment structure.

4. The structure according to any one of claims 1 to 2, wherein An equivalent phase of a region of the first partial substrate except the region of the hard mask coating layer is 2 / 3π, an equivalent phase of a region of the second partial substrate is 0, and an equivalent phase of the region of the hard mask coating layer is -2 / 3π. The region of the first partial substrate except the region of the hard mask coating layer is divided into two parts, and each part accounts for 2 / 15 of the total width of the lithography alignment structure; the two parts are arranged with intervals; The region of the second partial substrate is divided into three parts, and each part accounts for 2 / 15 of the total width of the lithography alignment structure; the three parts are arranged with intervals; The region of the hard mask coating layer is divided into two parts, and each part accounts for 1 / 6 of the total width of the lithography alignment structure.

5. The structure of any of claims 1-2, wherein An equivalent phase of a region of the first partial substrate except the region of the hard mask coating layer is 2 / 3π, an equivalent phase of a region of the second partial substrate is -2 / 3π, and an equivalent phase of the region of the hard mask coating layer is 0; The region of the first partial substrate except the region of the hard mask coating layer is divided into four parts, two of which account for 2 / 15 of the total width of the lithography alignment structure, and the other two account for 1 / 15 of the total width of the lithography alignment structure; the four parts are arranged with intervals; The region of the second partial substrate is divided into two parts, and each part accounts for 1 / 5 of the total width of the lithography alignment structure; the two parts are arranged with intervals; The region of the hard mask coating layer accounts for 1 / 5 of the total width of the lithography alignment structure.

6. The structure of any of claims 1-2, wherein An equivalent phase of a region of the first partial substrate except the region of the hard mask coating layer is 2 / 3π, an equivalent phase of a region of the second partial substrate is 0, and an equivalent phase of the region of the hard mask coating layer is -2 / 3π. The region of the first part of the substrate other than the region of the hard mask coating is divided into four parts, two of which account for 2 / 15 of the total width of the lithography alignment structure, and the other two account for 1 / 15 of the total width of the lithography alignment structure; The second part of the substrate region is divided into four parts, each accounting for 1 / 15 of the total width of the lithography alignment structure; the four parts are arranged at intervals; The region of the hard mask coating accounts for 1 / 3 of the total width of the lithography alignment structure.

7. The structure of any of claims 1-2, wherein The equivalent phase of the region of the first part of the substrate other than the region of the hard mask coating is 2 / 3π, the equivalent phase of the second part of the substrate region is 0, and the equivalent phase of the region of the hard mask coating is -2 / 3π; The region of the first part of the substrate other than the region of the hard mask coating is divided into four parts, two of which account for 2 / 15 of the total width of the lithography alignment structure, and the other two account for 1 / 15 of the total width of the lithography alignment structure; the four parts are arranged at intervals; The second part of the substrate region is divided into two parts, each accounting for 2 / 15 of the total width of the lithography alignment structure; the two parts are arranged at intervals; The region of the hard mask coating is divided into five parts, each accounting for 1 / 15 of the total width of the lithography alignment structure.

8. A method of manufacturing a lithographic alignment structure, characterized by, Comprising: providing an initial substrate; depositing a hard mask coating on one side of the initial substrate; depositing a photoresist coating on the side of the hard mask coating away from the initial substrate; the initial substrate covered with the photoresist coating as a first part of the substrate, and the region of the initial substrate not covered with the photoresist coating as a second part of the substrate region; lithography and etching to remove the hard mask coating and part of the initial substrate of the second part of the substrate region to form the second part of the substrate; lateral etching of the photoresist coating to expose part of the hard mask coating; etching the exposed hard mask coating; the hard mask coating is exactly contained in the first part of the substrate in the orthographic projection of the first part of the substrate; removing the photoresist coating.

9. The method of claim 8, wherein, The hard mask coating comprises a stack of one or more materials.

10. The method of claim 8, wherein, The photoresist coating comprises a photoresist, or a combined stack of a photoresist and an antireflection coating. The photoresist coating comprises a photoresist, or a combined stack of a photoresist and an antireflection coating.

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