CN111965961B - Positioning method and positioning mark for photoetching process - Google Patents

Abstract

The embodiment of the invention discloses a positioning method and a positioning mark for a photoetching process, wherein the method comprises the following steps: obtaining a first positioning mark formed by a first photomask manufacturing process, wherein the first positioning mark comprises a first side edge and a second side edge which are parallel to each other; obtaining a second positioning mark formed by a second photomask manufacturing process, wherein the second positioning mark comprises a third side edge and a fourth side edge, the third side edge is parallel to the first side edge, and the intersecting angle of the fourth side edge and the second side edge is less than 45 degrees; and determining the deviation between the third side edge and the first side edge according to the intersection angle and the intersection position of the fourth side edge and the second side edge. According to the invention, the offset of the photoetching pattern in one direction is amplified by comparing the first positioning mark with the second positioning mark and utilizing the intersection relation of the two layers of positioning marks, so that the technical problem that a semiconductor device cannot be accurately positioned due to limitation of the limit of human eyes and the alignment precision of equipment is solved, and the technical effect of intelligently improving the photoetching positioning precision is realized.

Description

Positioning method and positioning mark for photolithography process

technical field

Embodiments of the present invention relate to semiconductor technology, and in particular to a positioning method and a positioning mark used in a photolithography process.

Background technique

The photolithography process refers to a process that removes specific parts of the wafer surface film through a series of production steps. The photolithography process is first to establish a pattern on the surface of the wafer as close as possible to the size required in the design rules, and secondly to correctly position the pattern on the surface of the wafer. Because the final pattern is built up layer by layer on the surface of the wafer with multiple masks in a specific order, if the positioning is not accurate each time, the entire circuit will fail. Therefore, how to better perform positioning and calibration has become a key research project in the photolithography process.

Most of the lithography process positioning methods currently used are to transmit the mask pattern and the pattern on the wafer to the display system through the microscopic imaging system in the lithography equipment, and then realize it by manual alignment or automatic alignment of the equipment , due to the limitations of human eyes and equipment alignment accuracy, both manual alignment and automatic equipment alignment have the technical problem of not being able to accurately position semiconductor devices.

Contents of the invention

The invention provides a positioning method and a positioning mark for a photolithography process, so as to realize intelligence, improve the positioning precision of the photolithography, and improve the precision and quality of semiconductor finished products.

In the first aspect, an embodiment of the present invention provides a positioning method for a photolithography process, including:

Acquiring a first positioning mark formed by the first photomask process, where the first positioning mark includes a first side and a second side parallel to each other;

Obtaining the second positioning mark formed by the second photomask process, the second positioning mark includes a third side and a fourth side, the third side is parallel to the first side, and the fourth side and the the angle at which the second sides intersect is less than 45 degrees;

A deviation between the third side and the first side is determined based on an intersection angle and an intersection position of the fourth side and the second side.

Optionally, the determining the deviation between the third side and the first side according to the intersection angle and intersection position of the fourth side and the second side includes:

Determine the intersection angle and intersection position of the fourth side and the second side based on a preset plane coordinate system, the preset plane coordinate system is to take the first side as a coordinate axis and perpendicular to the second side A two-dimensional coordinate system with the direction of one side as the other coordinate axis and the endpoint of the first side as the origin;

determining the distance between the intersection position of the fourth side and the second side along a direction parallel to the first side according to the intersection angle and intersection position of the fourth side and the second side;

A deviation between the third side and the first side is determined based on the distance.

Optionally, the first positioning mark includes a cross positioning identification figure or a symmetrical polygonal positioning identification figure with adjacent sides perpendicular to each other, and the second positioning mark includes a symmetrical polygonal positioning identification figure with sloped sides.

Optionally, the graphic shapes of the first positioning mark and the second positioning mark are different, and the length of the second side of the first positioning mark in the direction of the first side is less than or equal to the fourth length of the second positioning mark. The length of the sides along the direction of the first side.

Optionally, the first positioning mark is located on the underlying metal plate or on the underlying mask covering the underlying metal plate, and the second positioning mark is located on the underlying metal plate or adjacent to the underlying masking plate. Covering on the top mask plate of the bottom metal plate.

Optionally, the first positioning mark and the second positioning mark are respectively formed on the adjacent bottom mask and the top mask by photolithography, electron beam or corrosion solvent, and the mask is used for A corresponding photolithography pattern is formed on the surface of the metal layer covering the substrate.

Optionally, the exposure window lengths of the bottom mask and the top mask are different.

Optionally, the first positioning mark further includes a fifth side, the second positioning mark further includes a sixth side, the fifth side is parallel to the second side, and the sixth side is parallel to the second side. The angle between one coordinate axis of the preset coordinate system is the same as the angle between the fourth side and the coordinate axis of the preset coordinate system, and the fifth side and the sixth side intersect, the length of the fifth side is greater than the length of the sixth side.

Optionally, the deviation between the third side and the first side is determined by the following formula:

h=2a*cotθ

Wherein, h is the distance, a is the deviation, and θ is the intersection angle.

In the second aspect, the embodiment of the present invention also provides a positioning mark for a photolithography process, including:

The first positioning mark provided on the first mask includes a first side and a second side parallel to each other;

The second positioning mark arranged on the second photomask includes a third side and a fourth side, the third side is parallel to the first side, and the fourth side intersects with the second side The angle is less than 45 degrees.

The present invention compares the first positioning mark and the second positioning mark on the adjacent metal layer or on the same circuit substrate, and utilizes the intersecting relationship between the two layers of positioning marks to amplify the offset of the photolithography pattern in one direction, and solves the problem caused by The limitations of the human eye and the alignment accuracy of equipment lead to the technical problem that semiconductor devices cannot be positioned accurately, and the technical effect of intelligently improving the positioning accuracy of lithography and improving the accuracy and quality of semiconductor products is realized.

Description of drawings

FIG. 1 is a flow chart of a positioning method for a photolithography process provided by Embodiment 1 of the present invention;

FIG. 2a is a schematic structural diagram of a semiconductor device provided by Embodiment 1 of the present invention;

FIG. 2b is a schematic structural diagram of a semiconductor device provided by Embodiment 1 of the present invention;

Fig. 3a is a schematic diagram of a first positioning mark provided by Embodiment 1 of the present invention;

FIG. 3b is a schematic structural diagram of another semiconductor device provided by Embodiment 1 of the present invention;

Fig. 3c is a schematic diagram of a second positioning mark provided by Embodiment 1 of the present invention;

Fig. 4a is a schematic diagram of a first positioning mark and a second positioning mark provided by Embodiment 1 of the present invention;

Fig. 4b is a schematic diagram of another first positioning mark and a second positioning mark provided by Embodiment 1 of the present invention;

FIG. 5 is a flow chart of a positioning method for a photolithography process provided by Embodiment 2 of the present invention;

Fig. 6a is a schematic diagram of a second positioning mark provided by Embodiment 2 of the present invention;

Fig. 6b is a schematic diagram of a first positioning mark and a second positioning mark provided by Embodiment 2 of the present invention;

FIG. 7 is a schematic structural diagram of a mask provided by Embodiment 2 of the present invention;

Fig. 8a is a schematic diagram of a first positioning mark provided by Embodiment 2 of the present invention;

Fig. 8b is a schematic diagram of another first positioning mark and a second positioning mark provided by Embodiment 2 of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for the convenience of description, only some structures related to the present invention are shown in the drawings but not all structures.

In order to make the purpose, technical solution and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application, and are not intended to limit the present application.

Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the steps as sequential processing, many of the steps may be performed in parallel, concurrently, or simultaneously. Additionally, the order of steps may be rearranged. A process may be terminated when its operations are complete, but may also have additional steps not included in the figure. A process may correspond to a method, function, procedure, subroutine, subroutine, or the like.

In addition, the terms "first", "second", etc. may be used herein to describe various directions, actions, steps or elements, etc., but these directions, actions, steps or elements are not limited by these terms. These terms are only used to distinguish a first direction, action, step or element from another direction, action, step or element. The terms "first", "second", etc. should not be interpreted as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present invention, "plurality" and "batch" mean at least two, such as two, three, etc., unless otherwise specifically defined.

The photolithography process refers to a process that removes specific parts of the wafer surface film through a series of production steps. The photolithography process is first to establish a pattern on the surface of the wafer as close as possible to the size required in the design rules, and secondly to correctly position the pattern on the surface of the wafer. Because the final pattern is built up layer by layer on the surface of the wafer with multiple masks in a specific order, if the positioning is not accurate each time, the entire circuit will fail. Therefore, how to better perform positioning and calibration has become a key research project in the photolithography process.

Embodiment one

FIG. 1 is a flow chart of a positioning method for a photolithography process provided by Embodiment 1 of the present invention. This embodiment is applicable to the case of performing a photolithography process on a semiconductor material, and the method can be executed by a processor. As shown in Figure 1, the positioning method for the photolithography process of this embodiment includes:

Step S110, acquiring a first positioning mark formed by the first photomask manufacturing process, the first positioning mark includes a first side and a second side parallel to each other.

Among them, the photomask manufacturing process refers to the production process of drawing the electronic circuit diagram that meets the requirements after testing into a photomask image. Firstly, the pattern on the mask plate needs to be transferred to the photoresist layer. After the mask plate and the photoresist layer are aligned, the properties and structure of the photoresist will change after exposure, that is, from the original soluble substance to the photoresist layer. Insoluble substances, or vice versa, and then remove the soluble parts by chemical solvents or developers, leaving a hole under the photoresist layer, and this hole will correspond to the opaque part of the mask correspond. Secondly, it is necessary to transfer the pattern from the photoresist to the wafer (wafer refers to the silicon wafer used in the production of silicon semiconductor integrated circuits. Because its shape is circular, it is called a wafer; it can be processed on a silicon wafer Various circuit element structures, and become IC products with specific electrical functions). This step is to remove the protective layer or film layer on the part of the wafer that is not protected by the photoresist through different etching methods, and finally remove the photoresist layer, so that the pattern on the mask plate is finally transferred to the wafer. circle on.

Specifically, in order to facilitate the positioning of the subsequent photolithography process, a positioning mark is usually designed on the edge of the mask. The positioning mark corresponding to the positioning mark of the plate is the first positioning mark in this embodiment, and the first positioning mark may include two sides parallel to each other. Fig. 2a is a schematic structural view of a semiconductor device provided by Embodiment 1 of the present invention. As shown in Fig. 2a, 10 is a metal layer, and 20 is a circuit substrate. A layer of metal layer 10 is placed on the metal layer 10, and a protective layer can be covered on the metal layer 10. The function of the protective layer is to protect the part that needs to be reserved in the metal layer 10 from being corroded. A mask can be covered on the protective layer. The stencil may include photolithographic patterns (such as circuit patterns, etc.) that have been tested to meet requirements, corresponding exposure windows, and positioning marks for positioning. Generally speaking, the positioning marks will be located at the edge of the mask. When light is irradiated from the top of the mask to the bottom, the material structure of the protective layer corresponding to the exposure window of the mask will change, and then the entire semiconductor device with the mask removed will be placed in a protection against the material structure change. The corrosion solvent for corroding the protective layer, the surface of the semiconductor device corresponding to the corroded position of the protective layer is exposed, and the exposed metal layer 10 corresponding to the protective layer where the material structure changes occurs is removed by other corrosion solvents or corrosion methods, and then washed After the protective layer covering the metal layer 10 is removed, the photolithography pattern on the mask plate can be transferred to the metal layer 10, and finally the metal layer shown in FIG. 2 is obtained. In this embodiment, a corrosion solvent can also be selected to directly target the part of the protective layer where the material structure changes and the metal layer 10 corresponding to the part of the protective layer where the material structure changes (that is, under the protective layer where the material structure changes. The corresponding metal layer) is etched, so that the photolithography pattern on the mask plate is transferred to the metal layer 10, and the positioning mark on the mask plate is transferred to the metal layer 10 in the same way. In this embodiment, after the semiconductor device completes a photomask process, the processor corresponding to the lithography equipment can be captured on the metal layer by microscopic equipment, laser equipment or other image acquisition equipment or used for the secondary photomask process. The positioning mark on the mask plate of the mask, this positioning mark includes two sides parallel to each other. FIG. 2b is a schematic structural diagram of another semiconductor device provided by Embodiment 1 of the present invention. As shown in FIG. 2 b , the first positioning mark is located at the edge of the metal layer 10 , the first positioning mark is a cross shape, and the first side of the first positioning mark is parallel to the second side.

Fig. 3a is a schematic diagram of a first positioning marker provided by Embodiment 1 of the present invention. As shown in FIG. 3 a , the first positioning mark is in the shape of a cross, the first side is 1, the second side is 2, and the first side and the second side are parallel to each other. In this embodiment, the shape of the first positioning mark can be various, as long as the first positioning mark is a symmetrical figure, and there is a group of sides parallel to each other.

Step S120, acquire the second positioning mark formed by the second photomask process, the second positioning mark includes a third side and a fourth side, the third side is parallel to the first side, and the fourth side An angle at which the side and the second side intersect is less than 45 degrees.

Specifically, FIG. 3b is a schematic structural diagram of another semiconductor device provided by an embodiment of the present invention. 10 is the top metal layer, 20 is the bottom metal layer (that is, the metal layer for the first photomask process), and 30 is the circuit substrate. When the semiconductor device is subjected to the second photomask process, the first photomask process is completed. The surface of the metal layer of the semiconductor device will be covered with a layer of top metal layer, which is the same as the first photomask process. The positioning mark of the mask plate used in the photomask process also generates a positioning mark (ie, the second positioning mark in this embodiment) at the edge, and the second positioning mark is used to judge the bottom layer according to the comparison with the first positioning mark. Whether there is an error in the positioning of the metal layer and the top metal layer. The processor corresponding to the lithography equipment can obtain the second positioning mark on the metal layer or on the mask used for the secondary photomask process through a microscopic equipment, a laser equipment or other image acquisition equipment. Fig. 3c is a schematic diagram of a second positioning mark provided by Embodiment 1 of the present invention. As shown in Figure 3c, the third side is 3, the fourth side is 4, the third side 3 is parallel to the first side of the first positioning mark, and the fourth side 4 is parallel to the second side of the first positioning identification. There is an intersection point on the sides, and the intersection angle between the fourth side and the second side is less than 45 degrees.

Step S130, determining the deviation between the third side and the first side according to the intersection angle and intersection position of the fourth side and the second side.

Fig. 4a is a schematic diagram of a first positioning mark and a second positioning mark provided by Embodiment 1 of the present invention. As shown in Figure 4a, when the first positioning mark and the second positioning mark are completely aligned, the third side of the second positioning mark coincides with the first side of the first positioning mark and the fourth side of the second positioning mark It intersects with the third side of the first positioning mark at a fixed point. Fig. 4b is a schematic diagram of another first positioning mark and a second positioning mark provided by Embodiment 1 of the present invention. As shown in Fig. 4b, when there is a positioning error between the first positioning mark and the second positioning mark, the lithography equipment The processor can determine the intersection angle and intersection position of the fourth side and the second side in a preset coordinate system, and the preset coordinate system can be based on the endpoint of the first side as the origin, so as to be parallel to the first side The direction is a coordinate system, and the direction perpendicular to the first side is a two-dimensional plane coordinate system of another coordinate system. The preset coordinate system can be obtained by obtaining the size identified by the first positioning and after a certain calculation. After the processor of the lithography equipment determines the intersection angle and intersection position between the fourth side and the second side, since the first positioning mark and the second positioning mark are both symmetrical figures, the third position can be obtained according to the preset deviation algorithm. The error between the side and the first side, that is, the distance between the third side and the first side (ie h in Figure 4b).

The beneficial effect of the first embodiment of the present invention is that by comparing the first positioning mark and the second positioning mark on the adjacent metal layer or on the same circuit substrate, the intersection relationship of the two layers of positioning marks is used to amplify the position of the photolithographic pattern in one direction. The offset solves the technical problem that semiconductor devices cannot be accurately positioned due to the limitations of human eyes and equipment alignment accuracy, and realizes the technical effect of intelligently improving the positioning accuracy of lithography and improving the accuracy and quality of semiconductor products.

Embodiment two

Embodiment 2 of the present invention is a further improvement on the basis of Embodiment 1. FIG. 5 is a flow chart of a positioning method for a photolithography process provided by Embodiment 2 of the present invention. As shown in FIG. 5, the positioning method for the photolithography process of this embodiment includes:

Step S210, acquiring a first positioning mark formed by the first photomask process, the first positioning mark including a first side and a second side parallel to each other.

Specifically, the first positioning mark in the embodiment of the present invention may have various shapes, as long as the first positioning mark is a symmetrical figure with two sides parallel to each other.

Step S220, acquire the second positioning mark formed by the second photomask process, the second positioning mark includes a third side and a fourth side, the third side is parallel to the first side, and the fourth side An angle at which the side and the second side intersect is less than 45 degrees.

Specifically, in this embodiment, the first positioning mark and the second positioning mark may also be located on the circuit substrate. Fig. 6a is a schematic diagram of a second positioning mark provided by Embodiment 2 of the present invention. As shown in Figure 6a, the third side 3 of the second positioning mark is parallel to the first side of the first positioning mark, and there is an intersection point between the fourth side 4 of the second positioning mark and the second side of the first positioning mark , and the intersection angle between the fourth side and the second side is less than 45 degrees (can be determined by the geometrical properties of a right triangle).

Step S230, determine the intersection angle and intersection position of the fourth side and the second side based on a preset plane coordinate system, the preset plane coordinate system is the first side as a coordinate axis, and the vertical The direction of the first side is another coordinate axis and a two-dimensional coordinate system with the endpoint of the first side as the origin.

Step S240, according to the intersection angle and intersection position of the fourth side and the second side, determine the intersection position of the fourth side and the second side along the direction parallel to the first side Pitch.

Step S250, determining the deviation between the third side and the first side according to the distance.

Specifically, the processor of the lithographic equipment can determine the intersection angle and intersection position between the fourth side and the second side in a preset coordinate system, and the preset coordinate system can be based on the endpoint of the first side as the origin, so that The direction parallel to the first side is a coordinate system, and the direction perpendicular to the first side is a two-dimensional plane coordinate system of another coordinate system. The preset coordinate system can obtain the size identified by the first positioning, after a certain calculated. After the processor of the lithography equipment determines the intersection angle and intersection position of the fourth side and the second side, the processor also needs to determine the distance between the intersection points of each group of fourth sides and the second side according to the geometric relationship. The distance along the direction of the first side, and then the deviation between the third side and the first side is obtained through a preset algorithm. Fig. 6b is a schematic diagram of a first positioning mark and a second positioning mark provided by Embodiment 2 of the present invention. As shown in Figure 6b, when the first positioning mark is not aligned with the second positioning mark, that is, when the first side of the first positioning mark does not coincide with the third side of the second positioning mark, since the first positioning mark and the second positioning mark The second positioning marks are all symmetrical figures, and the processor can determine the distance between the two groups of fourth sides and the second side edges parallel to the first side direction in the preset coordinate system according to the geometric relationship (that is, Fig. 6 h) in, and then obtain the error between the third side and the first side through the preset deviation algorithm, that is, the distance value between the third side and the first side (that is, a in Figure 6b), or Determine the distance between the intersection point of the second side and the fourth side and the preset intersection point when the first positioning mark and the second positioning mark in the preset coordinate system are misaligned according to the geometric relationship, and the preset intersection point It refers to the intersection point of the second side and the fourth side based on the same coordinate system when the first positioning mark and the second positioning mark are fully aligned, and then the third side and the first side are calculated by the preset deviation formula error between.

In this embodiment, the first positioning mark includes a cross positioning identification figure or a symmetrical polygonal positioning identification figure with adjacent sides perpendicular to each other, and the second positioning mark includes a symmetrical polygonal positioning identification figure with sloped sides.

Specifically, since the second positioning mark has at least one side that intersects the first positioning mark, the second positioning mark can be a symmetrical polygon with a slope on the side in this embodiment, and the second positioning mark also needs to have one side The side can be parallel to the first side of the first positioning mark.

In this embodiment, the graphic shapes of the first positioning mark and the second positioning mark are different, and the length of the second side of the first positioning mark in the direction of the first side is less than or equal to that of the second positioning mark. The length of the fourth side along the direction of the first side.

In this embodiment, the first positioning mark can also be located on the bottom mask plate covering the bottom metal plate or the bottom metal plate, and the second positioning mark can also be located on the bottom mask plate adjacent to the bottom mask plate. The adjacent top mask covering the bottom metal plate or covering the bottom metal plate.

Specifically, the first positioning mark can also be located on the bottom metal plate of the semiconductor device or on the bottom mask plate covering the bottom metal plate. The second positioning mark is the same as the first positioning mark, and the second positioning mark can also be located on the semiconductor device. On the bottom metal plate of the device or on the top mask of the bottom metal plate, the top mask is adjacent to the bottom mask, and the bottom mask can refer to the semiconductor device covered in the first photomask process. The mask plate on the surface of the metal layer, the top layer mask plate may refer to the mask plate used when performing the second photomask process on the semiconductor device.

In this embodiment, the first positioning mark and the second positioning mark are respectively formed on the adjacent bottom mask and top mask by photolithography, electron beam or corrosion solvent, and the mask It is used to form a corresponding photolithographic pattern on the surface of the metal layer covering the substrate.

In this embodiment, the exposure window lengths of the bottom mask and the top mask are different.

Specifically, FIG. 7 is a schematic structural diagram of a mask provided by Embodiment 2 of the present invention. As shown in FIG. 7 , 10 is a mask plate, 20 is a metal layer, and s is the length of an exposure window. The length of the exposure window of the bottom mask plate corresponding to the first photomask process and the top mask plate corresponding to the second photomask process in this embodiment may be different, and the length of the exposure window depends on the mask to be produced in this mask process. Graphics, that is, which parts of the metal layer need to be preserved, and the parts that need to be preserved will not be opened at the corresponding positions of the mask.

In this embodiment, the first positioning mark further includes a fifth side, the second positioning mark further includes a sixth side, the fifth side is parallel to the second side, and the sixth side The included angle between a side and a coordinate axis of the preset coordinate system is the same as the included angle between the fourth side and the coordinate axis of the preset coordinate system, and the fifth side and the sixth side The sides intersect, and the length of the fifth side is greater than the length of the sixth side.

Specifically, FIG. 8a is a schematic diagram of a first positioning marker provided in Embodiment 2 of the present invention, and FIG. 8b is a schematic diagram of another first positioning marker and a second positioning marker provided in Embodiment 2 of the present invention. As shown in Figures 8a and 8b, the straight line C1 is parallel to the third side 3, the sixth side 6 of the second positioning mark intersects with the fifth side of the first positioning mark, and the sixth side 6 and the fifth side of the first positioning mark The four sides 4 are distributed symmetrically along C1 (that is, the included angle between the sixth side and a coordinate axis of the preset coordinate system is the same as the included angle between the fourth side and a coordinate axis of the preset coordinate system). In this implementation, the length of the fifth side may also be greater than the length of the sixth side, so as to ensure that the fifth side and the sixth side can intersect.

In this embodiment, the deviation between the third side and the first side can be determined by the following formula:

h=2a*cotθ

Wherein, h is the distance, a is the deviation, and θ is the intersection angle.

Specifically, when the processor of the lithographic equipment determines the intersection position between the fourth side and the second side according to the intersection angle (that is, θ in the formula) and the intersection position of the fourth side and the second side along the line parallel to the first side After the distance h in the direction of one side, the deviation between the third side and the first side can be determined according to the above formula, that is, a in the formula, that is to say, by enlarging the first positioning mark and the second positioning mark The deviation along one of the coordinate axes of the preset coordinate system enables the production staff to more accurately position the semiconductor device and improve the manufacturing accuracy of the semiconductor device.

The beneficial effect of the second embodiment of the present invention is that by comparing the first positioning mark and the second positioning mark on the adjacent metal layer or on the same circuit substrate, and the first positioning mark is different from the second positioning mark, the second positioning mark is The symmetrical figure with a slope on the side uses the intersection relationship and geometric relationship of the two-layer positioning marks to amplify the offset of the photolithography figure in one direction, which solves the problem of inaccurate alignment of semiconductors due to the limitations of human eyes and equipment alignment accuracy. The technical problem of device positioning has achieved the technical effect of intelligently improving the positioning accuracy of lithography and improving the precision and quality of semiconductor products.

Note that the above are only preferred embodiments of the present invention and applied technical principles. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and can also include more other equivalent embodiments without departing from the concept of the present invention, and the present invention The scope is determined by the scope of the appended claims.

Claims (8)

1. A positioning method for photolithography process, characterized in that, comprising: Acquiring a first positioning mark formed by the first photomask process, where the first positioning mark includes a first side and a second side parallel to each other; Obtaining the second positioning mark formed by the second photomask process, the second positioning mark includes a third side and a fourth side, the third side is parallel to the first side, and the fourth side and the the angle at which the second sides intersect is less than 45 degrees; determining an offset between the third side and the first side based on an intersection angle and an intersection position of the fourth side and the second side; The determining the deviation between the third side and the first side according to the intersection angle and intersection position of the fourth side and the second side includes: Determine the intersection angle and intersection position of the fourth side and the second side based on a preset plane coordinate system, the preset plane coordinate system is to take the first side as a coordinate axis and perpendicular to the second side A two-dimensional coordinate system with the direction of one side as the other coordinate axis and the endpoint of the first side as the origin; determining the distance between the intersection position of the fourth side and the second side along a direction parallel to the first side according to the intersection angle and intersection position of the fourth side and the second side; A deviation between the third side and the first side is determined based on the distance. 2. The positioning method for photolithography according to claim 1, wherein the first positioning mark comprises a cross positioning identification pattern or a symmetrical polygonal positioning identification pattern whose adjacent sides are perpendicular to each other, and the first positioning mark The second positioning mark includes a symmetrical polygonal positioning identification figure with a slope on the side. 3. The positioning method for photolithography process according to claim 1, characterized in that, the graphic shapes of the first positioning mark and the second positioning mark are different, and the second side edge of the first positioning mark The length in the direction of one side is less than or equal to the length in the direction of the first side of the fourth side of the second positioning mark. 4. The positioning method for a photolithography process according to claim 1, wherein the first positioning mark is located on the underlying metal plate or on the underlying mask covering the underlying metal plate, and the second positioning mark is The positioning mark is located on the bottom metal plate or on the top mask adjacent to the bottom mask and covering the bottom metal plate. 5. The positioning method for a photolithography process according to claim 4, wherein the first positioning mark and the second positioning mark are respectively formed on adjacent On the bottom mask and the top mask, the mask is used to form a corresponding photolithographic pattern on the surface of the metal layer covering the substrate. 6 . The positioning method for a photolithography process according to claim 5 , wherein the exposure window lengths of the bottom mask and the top mask are different. 7 . 7. The positioning method for photolithography process according to claim 2, characterized in that, the first positioning mark further comprises a fifth side, the second positioning mark further comprises a sixth side, and the fifth The side is parallel to the second side, and the included angle between the sixth side and one coordinate axis of the preset plane coordinate system is the same as the angle between the fourth side and the preset plane coordinate system. The included angles of the coordinate axes are the same, the fifth side intersects with the sixth side, and the length of the fifth side is greater than the length of the sixth side. 8. The positioning method for a photolithography process according to claim 1, wherein the deviation between the third side and the first side is determined by the following formula: h=2a*cotθ Wherein, h is the distance, a is the deviation, and θ is the intersection angle.

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