Semiconductor structure, mask layout and measurement method

Abstract

The invention discloses a semiconductor structure, a mask layout and a measuring method, and the structure comprises a substrate which comprises an alignment identification region; the alignment identification frame is located in the substrate of the alignment identification area, and the alignment identification frame is provided with a corner; the measurement mark is located in the alignment mark frame; and the auxiliary identifier group comprises a plurality of auxiliary alignment identifiers, the auxiliary alignment identifiers are respectively located at the corners of the alignment identifier frame, the auxiliary alignment identifiers have right-angle corners, and the central point of the alignment identifier frame, the central point of the measurement identifier and the central point of the auxiliary alignment group coincide. The center point of the alignment identification frame, the center point of the measurement identification and the center point of the auxiliary identification group coincide, namely, the vector distance between the measurement identification and the auxiliary identification group is zero, and correspondingly, the measurement identification can be directly positioned through the center coordinate point of the alignment identification frame, so that the measurement accuracy is improved. Therefore, the measurement mark can be directly scanned and the overlay error can be measured, so that the scanning speed and accuracy of the measurement mark can be improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of semiconductor manufacturing, and in particular to a semiconductor structure, a mask layout, and a measurement method. Background Art

[0002] With the continuous advancement of technology nodes, the overlay error is getting smaller and smaller. The overlay error measurement (OVL) after photolithography development (ADI) uses a diffraction-based overlay mark (DBO mark). Affected by the etching process, the OVL value of the same measurement point from after development (ADI) to after etching (AEI) will have a fixed difference (AEI_ADI offset). In order to obtain a fixed difference to correct ADI, it is necessary to design a post-etching measurement mark to obtain OVL.

[0003] Currently, the speed and accuracy of measuring marks after scanning etching still needs to be improved. Summary of the invention

[0004] The problem solved by the embodiments of the present invention is to provide a semiconductor structure, a mask layout, and a measurement method, which can improve the speed and accuracy of scanning the measurement mark.

[0005] To solve the above problems, an embodiment of the present invention provides a semiconductor structure, comprising: a substrate, comprising an alignment mark area; an alignment mark frame, located in the substrate of the alignment mark area, the alignment mark frame having a corner; a measurement mark, located in the alignment mark frame; an auxiliary mark group, comprising a plurality of auxiliary alignment marks, the auxiliary alignment marks are respectively located at the corners of the alignment mark frame, the auxiliary alignment marks have right-angle corners, and the center points of the alignment mark frame, the measurement mark and the auxiliary alignment group coincide with each other.

[0006] Optionally, the measurement marks are symmetrical to each other in a first direction and a second direction, and the first direction and the second direction are perpendicular to each other.

[0007] Optionally, the measurement mark includes a measurement layer extending along the first direction and arranged in parallel and at intervals along the second direction.

[0008] Optionally, in the alignment mark frame, the plurality of auxiliary alignment marks are symmetrical to each other in a first direction and a second direction, and the first direction and the second direction are perpendicular to each other.

[0009] Optionally, the alignment mark frame is in the shape of a square ring.

[0010] Optionally, a corner of the alignment mark frame is a right angle, and the corner of the alignment mark frame contacts a right-angle corner of the auxiliary alignment mark.

[0011] Optionally, the shape of the auxiliary alignment mark includes one or more of square, L-shaped and cross-shaped.

[0012] Optionally, the auxiliary alignment mark is a solid pattern structure; or, the auxiliary alignment mark includes a plurality of sub-auxiliary alignment marks arranged at intervals, and the plurality of sub-auxiliary alignment marks arranged at intervals constitute the auxiliary alignment mark.

[0013] Optionally, the sub-auxiliary alignment mark includes a bar structure or a through-hole structure.

[0014] Optionally, the distance between adjacent sub-auxiliary alignment marks is 35 nanometers to 2000 nanometers.

[0015] Correspondingly, an embodiment of the present invention further provides a mask pattern, comprising: an alignment mark frame graphic, the alignment mark frame graphic having a corner; a measurement mark graphic, the measurement mark graphic being located in the alignment mark frame graphic; an auxiliary mark group graphic, the auxiliary mark group graphic comprising a plurality of auxiliary alignment mark graphics, the auxiliary alignment mark graphics being respectively located at the corners of the alignment mark frame graphic, and the auxiliary alignment mark graphic having a right-angle corner; wherein the center point of the alignment mark frame graphic, the center point of the measurement mark graphic and the center point of the auxiliary mark group coincide with each other.

[0016] Optionally, the measurement mark pattern is symmetrical in a first direction and a second direction, and the first direction and the second direction are perpendicular to each other.

[0017] Optionally, the measurement identification pattern includes measurement layer patterns extending along the first direction and arranged in parallel and at intervals along the second direction.

[0018] Optionally, the alignment mark frame graphic is in the shape of a square ring.

[0019] Optionally, a corner of the alignment mark frame graphic is a right angle, and the corner of the alignment mark frame graphic is in contact with a right-angle corner of the auxiliary alignment mark graphic.

[0020] Optionally, in the alignment mark frame graphic, a plurality of the auxiliary alignment mark graphics are symmetrical to each other in a first direction and a second direction, and the first direction and the second direction are perpendicular to each other.

[0021] Optionally, the shape of the auxiliary alignment mark pattern includes one or more of a square, an L-shape and a cross-shape.

[0022] Optionally, the auxiliary alignment mark pattern is a solid pattern; or, the auxiliary alignment mark pattern includes a plurality of sub-auxiliary alignment mark patterns arranged at intervals, and the plurality of sub-auxiliary alignment mark patterns arranged at intervals constitute the auxiliary alignment mark pattern.

[0023] Optionally, the type of the sub-auxiliary alignment mark pattern includes a bar pattern or a through-hole pattern.

[0024] Correspondingly, an embodiment of the present invention further provides a measurement method, comprising: providing a semiconductor structure provided by an embodiment of the present invention; obtaining a center coordinate point of the alignment mark frame; scanning the measurement mark according to the center coordinate point, and calculating an overlay error value.

[0025] Compared with the prior art, the technical solution of the embodiment of the present invention has the following advantages:

[0026] In a semiconductor structure provided by an embodiment of the present invention, an alignment mark frame is located in the substrate of the alignment mark area, a measurement mark is located in the alignment mark frame, the alignment mark frame has a corner, an auxiliary alignment mark is located at the corner of the alignment mark frame, the auxiliary alignment mark has a right-angle corner, and the center point of the alignment mark frame, the center point of the measurement mark and the center point of the auxiliary mark group coincide with each other; wherein the auxiliary alignment marks are respectively located at the corners of the alignment mark frame, and the relative positions of the auxiliary alignment marks and the measurement marks are fixed, thereby reducing the dependence of the selection of the auxiliary alignment marks on the surrounding environment, and the center point of the alignment mark frame, the center point of the measurement mark and the center point of the auxiliary mark group coincide with each other, which means that the vector distance between the measurement mark and the auxiliary mark group is zero, and accordingly, the measurement mark can be directly located through the center coordinate point of the alignment mark frame, that is, the measurement mark can be directly scanned and the overlay error can be measured, thereby improving the speed and accuracy of scanning the measurement mark. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram corresponding to a semiconductor structure;

[0028] Figures 2 to 6 is a schematic structural diagram of an embodiment of a semiconductor structure of the present invention;

[0029] Figures 7 to 11 The mask of the present invention Figure 1 Schematic diagram corresponding to the embodiment;

[0030] Fig.12 It is a flow chart of the steps of an embodiment of the testing method of the present invention. DETAILED DESCRIPTION

[0031] At present, the speed and accuracy of measuring mark scanning still need to be improved. The reasons why its performance needs to be improved are analyzed in combination with a semiconductor structure.

[0032] Figure 1 It is a structural schematic diagram corresponding to a semiconductor structure.

[0033] The substrate 10 includes an alignment mark area 11 ; an alignment mark frame 20 located in the substrate 10 in the alignment mark area 11 , wherein the alignment mark frame 20 has a corner; and a measurement mark 21 located in the alignment mark frame 20 .

[0034] It has been found that in the process of scanning and measuring the measurement mark 21, it is necessary to find a right-angle pattern (such as Figure 1 The right-angle corner P1 of the virtual pattern 31 in the cutting path area 16 is obtained, and the coordinates of the right-angle corner are input, and the coordinate point of the right-angle corner is moved a fixed vector distance S1 to identify the measurement mark 21 in the alignment mark frame 20. In the process of scanning and measuring the measurement mark 21 through the electron scanning microscope, it is necessary to measure the measurement mark 21 once at 0° and 180°. Since the right-angle corner P1 of the virtual pattern 31 in each cutting path area 16 is not the same, therefore, in the process of scanning and measuring the measurement mark 21, the coordinate point of the right-angle corner P1 of the virtual pattern 31 needs to be re-input at 0° and 180° for the measurement mark 21, and a certain vector distance needs to be re-moved to identify the measurement mark in the alignment mark frame 20, which results in a relatively low rate and accuracy of scanning the measurement mark.

[0035] In order to solve the technical problem, an embodiment of the present invention provides a semiconductor structure, including: a substrate, including an alignment mark area; an alignment mark frame, located in the substrate of the alignment mark area, the alignment mark frame having a corner; a measurement mark, located in the alignment mark frame; an auxiliary mark group, including a plurality of auxiliary alignment marks, the auxiliary alignment marks are respectively located at the corners of the alignment mark frame, the auxiliary alignment marks have right-angle corners, and the center points of the alignment mark frame, the measurement mark and the auxiliary alignment group coincide with each other.

[0036] In a semiconductor structure provided by an embodiment of the present invention, an alignment mark frame is located in the substrate of the alignment mark area, a measurement mark is located in the alignment mark frame, the alignment mark frame has a corner, an auxiliary alignment mark is located at the corner of the alignment mark frame, the auxiliary alignment mark has a right-angle corner, and the center point of the alignment mark frame, the center point of the measurement mark and the center point of the auxiliary mark group coincide with each other; wherein the auxiliary alignment marks are respectively located at the corners of the alignment mark frame, and the relative positions of the auxiliary alignment marks and the measurement marks are fixed, thereby reducing the dependence of the selection of the auxiliary alignment marks on the surrounding environment, and the center point of the alignment mark frame, the center point of the measurement mark and the center point of the auxiliary mark group coincide with each other, which means that the vector distance between the measurement mark and the auxiliary mark group is zero, and accordingly, the measurement mark can be directly located through the center coordinate point of the alignment mark frame, that is, the measurement mark can be directly scanned and the overlay error can be measured, thereby improving the speed and accuracy of scanning the measurement mark.

[0037] In order to make the above-mentioned purposes, features and advantages of the embodiments of the present invention more obvious and understandable, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0038] Figures 2 to 6 It is a structural schematic diagram corresponding to an embodiment of a semiconductor structure of the present invention.

[0039] The semiconductor structure includes: a substrate 100, including an alignment mark area 101; an alignment mark frame 106, located in the substrate 100 in the alignment mark area 101, and the alignment mark frame 106 has a corner; a measurement mark 110, located in the alignment mark frame 106; an auxiliary mark group (not shown), including a plurality of auxiliary alignment marks 108, the auxiliary alignment marks 108 are respectively located at the corners of the alignment mark frame 106, the auxiliary alignment marks 108 have right-angle corners, and the center points of the alignment mark frame 106, the measurement mark 110, and the auxiliary alignment group coincide with each other.

[0040] The auxiliary alignment marks 108 are respectively located at the corners of the alignment mark frame 106. The relative positions of the auxiliary alignment marks 108 and the measurement marks 110 are fixed, thereby reducing the dependence of the selection of the auxiliary alignment marks 108 on the surrounding environment. Moreover, the center point of the alignment mark frame 106, the center point of the measurement mark 110 and the center point of the auxiliary mark group coincide with each other, which means that the vector distance between the measurement mark 110 and the auxiliary mark group is zero. Accordingly, the measurement mark 110 can be directly positioned through the center coordinate point of the alignment mark frame 106, and the measurement mark 110 can be directly scanned and the overlay error can be measured, thereby improving the scanning speed and accuracy of the measurement mark 110.

[0041] The substrate 100 provides a process platform for setting up a semiconductor structure.

[0042] It should be noted that with the continuous advancement of technology nodes, the overlay error is getting smaller and smaller. The overlay error measurement (OVL) after lithography development (ADI) uses a diffraction-based overlay mark (DBO mark). Affected by the etching process, the OVL value of the same measurement point from after development (ADI) to after etching (AEI) will have a fixed difference (AEI_ADI offset). In order to obtain a fixed difference to correct ADI, it is necessary to design a post-etching measurement mark 110 to obtain OVL.

[0043] By providing the alignment mark area 101 in the substrate 100 , it is helpful to align the measurement instrument with the substrate 100 , thereby achieving measurement of the measurement mark 110 after etching to achieve OVL.

[0044] Meanwhile, the alignment mark area 101 is also an area for forming an alignment mark frame 106 .

[0045] It should be noted that, as an example, the substrate 100 further includes a device region 102 for forming a device structure.

[0046] Specifically, semiconductor devices such as transistors and capacitors may be formed in the substrate 100 in the device region 102 , and functional structures such as resistor structures and conductive structures may also be formed in the substrate 100 in the device region 102 .

[0047] The alignment mark frame 106 is used to align the measuring instrument with the substrate 100. At the same time, it is also beneficial to set the measurement mark 110 in the alignment mark frame 106 to reduce the influence of the peripheral pattern of the alignment mark area 101 on the measurement mark 110, which can further improve the accuracy of measuring the overlay error of the measurement mark 110.

[0048] It should be noted that the alignment mark frame 106 has corners. In the process of setting the auxiliary mark group, the corners of the alignment mark frame 106 can be used to make the auxiliary mark group contact the corners of the alignment mark frame 106, thereby reducing the dependence of the selection of the auxiliary alignment mark 108 on the surrounding environment.

[0049] As an example, the alignment mark frame 106 is in the shape of a square ring.

[0050] Specifically, in the formation process of the alignment mark frame 106, by setting the alignment mark frame 106 to a square ring shape, the process difficulty is reduced and the process compatibility is high. At the same time, the square ring shape has a corner. In the process of setting the auxiliary mark group, the corner of the alignment mark frame 106 can be directly used to make the corner of the auxiliary mark group contact with the corner of the alignment mark frame 106, thereby reducing the dependence of the auxiliary alignment mark 108 on the surrounding environment. Moreover, the corner of the auxiliary mark group is in contact with the corner of the alignment mark frame 106, which means that the center point of the area enclosed by the auxiliary mark group can be consistent with the center point of the alignment mark frame 106, which means that the vector distance between the measurement mark 110 and the auxiliary mark group is zero. Accordingly, the measurement mark 110 can be directly located through the center coordinate point of the alignment mark frame 106, so that the measurement mark 110 can be directly scanned and the overlay error can be measured, thereby improving the scanning rate and accuracy of the measurement mark 110.

[0051] In this embodiment, the corner of the alignment mark frame 106 is a right angle, and the corner of the alignment mark frame 106 is in contact with the right angle corner of the auxiliary alignment mark 108 .

[0052] Specifically, the corners of the alignment mark frame 106 are right angles, and the corners of the alignment mark frame 106 are in contact with the right-angled corners of the auxiliary alignment mark 108, so that the center point of the area enclosed by multiple auxiliary alignment marks 108 can be consistent with the center point of the alignment mark frame 106, and the corners of the alignment mark frame 106 are in contact with the right-angled corners of the auxiliary alignment mark 108. In the process of scanning and measuring the measurement mark 110, the measuring instrument can easily identify patterns with right angles, thereby improving the measurement speed and saving measurement time.

[0053] The OVL values ​​of the same measurement point from after development (ADI) to after etching (AEI) will have a fixed difference (AEI_ADIoffset). In order to obtain a fixed difference to calibrate ADI, it is necessary to design a post-etching measurement mark 110 (AEI Mark) to obtain OVL.

[0054] As an example, the measurement mark 110 is a post-etching measurement mark 110 .

[0055] In this embodiment, the measurement mark 110 is in the first direction (eg Figure 2 X direction) and the second direction (as shown in Figure 2 The first direction and the second direction are symmetrical with each other, and the first direction and the second direction are perpendicular to each other.

[0056] Specifically, in the process of scanning and measuring the measurement mark 110, it is necessary to measure the measurement mark 110 once at 0° and 180° respectively. By setting the measurement mark 110 to be symmetrical in the first direction and the second direction, the measurement mark 110 can be kept consistent at 0° and 180°. This means that in the process of scanning and measuring the measurement mark 110, only one angle between 0° and 180° needs to be selected to achieve the measurement of the measurement mark 110, thereby further improving the scanning rate of the measurement mark 110.

[0057] As an example, the measurement mark 110 includes a measurement layer extending along a first direction and arranged in parallel and spaced relation along a second direction, so that the measurement layer is symmetrical with each other in the first direction and the second direction. Accordingly, in the process of scanning and measuring the measurement mark 110, only one angle between 0° and 180° needs to be selected to achieve the measurement of the measurement mark 110, thereby further improving the scanning rate of the measurement mark 110.

[0058] It should be noted that, in the process of scanning and measuring the measurement mark 110, it is necessary to find a rectangular pattern outside the alignment mark area 101 and input the rectangular coordinates. By setting the auxiliary alignment mark 108 at the corner of the alignment mark frame 106, and the auxiliary alignment marks 108 all have right-angle corners, it is no longer necessary to find a rectangular pattern outside the alignment mark area 101, but directly use the right-angle corner of the auxiliary alignment mark 108. Since the center point of the alignment mark frame 106, the center point of the measurement mark 110 and the center point of the auxiliary alignment group coincide with each other, it means that the measurement mark 110 The vector distance between the auxiliary mark group and the auxiliary mark group is zero. Accordingly, the measuring instrument does not need to be moved. The measurement mark 110 can be directly positioned through the center coordinate point of the alignment mark frame 106, and the measurement mark 110 can be directly scanned and the overlay error can be measured, thereby improving the scanning speed and accuracy of the measurement mark 110. At the same time, by utilizing the right-angle corners of the auxiliary alignment mark 108, the influence of the outer right-angle pattern of the alignment mark area 101 is reduced, so that the auxiliary alignment mark 108 can be reused in different measurement environments, and only the center coordinate point of the alignment mark frame 106 needs to be changed.

[0059] Specifically, the center coordinate point of the alignment mark frame 106 can be obtained by calculating the RFL file.

[0060] As an example, in the alignment mark frame 106, a plurality of the auxiliary alignment marks 108 are arranged in a first direction (eg Figure 2 X direction) and the second direction (as shown in Figure 2 The first direction and the second direction are symmetrical with each other, and the first direction and the second direction are perpendicular to each other.

[0061] Specifically, the multiple auxiliary alignment marks 108 are symmetrical with each other in the first direction and the second direction, and the first direction and the second direction are perpendicular to each other, so that the center point of the area enclosed by the multiple auxiliary alignment marks 108 coincides with the center point of the measurement mark 110, which means that the vector distance between the measurement mark 110 and the auxiliary mark group is zero.

[0062] As an example, the shape of the auxiliary alignment mark 108 includes one or more of a square, an L-shape, and a cross-shape.

[0063] It should be noted that the square, L-shaped and cross-shaped shapes all have right-angled corners. In the process of scanning and measuring the measurement mark 110, the measuring instrument can easily identify patterns with right angles, thereby improving the measurement speed and saving measurement time. At the same time, the auxiliary alignment marks 108 all have right-angled corners, so there is no need to look for right-angled patterns outside the alignment mark area 101. Instead, the right-angled corners of the auxiliary alignment marks 108 are directly used. Since the center point of the alignment mark frame 106, the center point of the measurement mark 110 and the center point of the auxiliary alignment group coincide with each other, it means that the vector distance between the measurement mark 110 and the auxiliary mark group is zero. Accordingly, the measuring instrument does not need to move, and the measurement mark 110 can be directly located through the center coordinate point of the alignment mark frame 106, so that the measurement mark 110 can be directly scanned and the overlay error can be measured.

[0064] In this embodiment, the auxiliary alignment mark 108 is a solid pattern structure.

[0065] Specifically, Figure 3 As shown, the auxiliary alignment mark 108 includes a square solid pattern, an L-shaped solid pattern, and a cross-shaped solid pattern.

[0066] In other embodiments, the auxiliary alignment mark includes a plurality of sub-auxiliary alignment marks arranged at intervals, and the plurality of sub-auxiliary alignment marks arranged at intervals constitute the auxiliary alignment mark.

[0067] It should be noted that although the auxiliary alignment mark 108 includes a plurality of sub-auxiliary alignment marks 120 arranged at intervals, the overall outline of the auxiliary alignment mark 108 formed by the plurality of sub-auxiliary alignment marks 120 arranged at intervals has right-angle corners, so there is no need to look for a right-angle pattern outside the alignment mark area 101, but the right-angle corners of the auxiliary alignment mark 108 can be directly used.

[0068] like Figures 4 to 6 As shown, the sub-auxiliary alignment mark 120 includes a bar structure or a through-hole structure.

[0069] Specifically, Figure 4As shown, the auxiliary alignment mark 120 includes a first direction (eg Figure 4 X direction) and extends along the second direction (as shown in Figure 4 The strip structures are arranged at intervals (as shown in the Y direction), and some of the strip structures are concave or convex inwardly relative to the remaining strip structures.

[0070] like Figure 5 As shown, the auxiliary alignment mark 120 includes a second direction (such as Figure 5 ) and extends along a first direction (as shown in the Y direction Figure 5 The strip structures are arranged at intervals (as shown in the X direction), and some of the strip structures are concave or convex inwardly relative to the remaining strip structures.

[0071] like Figure 6 As shown, the auxiliary alignment mark 120 includes a first direction (eg Figure 6 X direction) are arranged in parallel and spaced apart and along a second direction (as shown in Figure 6 The through-hole structure is arranged in parallel with each other (as shown in the Y direction).

[0072] It should be noted that the distance between adjacent sub-auxiliary alignment marks 120 should not be too small or too large. If the distance between the sub-auxiliary alignment marks 120 is too small, the probability of overlapping the sub-auxiliary alignment marks 120 increases, affecting the accuracy of scanning the measurement mark 110 and measuring the overlay error. If the distance between the sub-auxiliary alignment marks 120 is too large, it is easy to cause the area occupied by the auxiliary mark group to be too large, and too much of the area of ​​the measurement mark 110 is occupied, increasing the difficulty of subsequent scanning of the measurement mark 110 and measuring the overlay error. For this reason, in this embodiment, the distance between adjacent sub-auxiliary alignment marks 120 is 35 nanometers to 2000 nanometers.

[0073] Accordingly, an embodiment of the present invention further provides a mask layout. Figures 7 to 11 The mask of the present invention Figure 1 Schematic diagram corresponding to the embodiment.

[0074] The mask pattern includes: an alignment mark frame graphic 206, wherein the alignment mark frame graphic 206 has a corner; a measurement mark graphic 210, wherein the measurement mark graphic 210 is located in the alignment mark frame graphic 206; an auxiliary mark group graphic (not shown), wherein the auxiliary mark group graphic includes a plurality of auxiliary alignment mark graphics 208, wherein the auxiliary alignment mark graphics 208 are respectively located at the corners of the alignment mark frame graphic 206, and the auxiliary alignment mark graphics 208 have a right-angle corner; wherein the center point of the alignment mark frame graphic 206, the center point of the measurement mark graphic 210, and the center point of the auxiliary mark group coincide with each other.

[0075] The alignment mark frame graphic 206 is used to form an alignment mark frame to achieve alignment between the measuring instrument and the substrate. At the same time, it is also beneficial to set the measurement mark graphic 210 in the alignment mark frame graphic 206, reduce the influence of the measurement mark graphic 210 on the measurement mark graphic 210 by the peripheral pattern, and further improve the accuracy of measuring the measurement mark overlay error formed by the measurement mark graphic 210.

[0076] It should be noted that the alignment mark frame graphic 206 has a corner. In the process of setting the auxiliary mark group graphic, the corner of the alignment mark frame graphic 206 can be used to make the auxiliary mark group graphic contact with the corner of the alignment mark frame graphic 206, thereby reducing the dependence of the selection of the auxiliary alignment mark graphic 208 on the surrounding environment.

[0077] As an example, the alignment mark frame graphic 206 is in the shape of a square ring.

[0078] Specifically, by setting the alignment mark frame graphic 206 to a square ring shape, the process difficulty is reduced and the process compatibility is high in the process of using the alignment mark frame graphic 206 to form the alignment mark frame. At the same time, the square ring shape has a corner. In the process of setting the auxiliary mark group graphic, the corner of the alignment mark frame graphic 206 can be directly used to make the corner of the auxiliary mark group graphic contact with the corner of the alignment mark frame graphic 206, thereby reducing the dependence of the auxiliary alignment mark graphic 208 on the surrounding environment. Moreover, the corner of the auxiliary mark group graphic contacts with the corner of the alignment mark frame graphic 206, which means that the center point of the area enclosed by the auxiliary mark group graphic can be consistent with the center point of the alignment mark frame graphic 206, which means that the vector distance between the measurement mark graphic 210 and the auxiliary mark group graphic is zero

[0079] In this embodiment, the corner of the alignment mark frame pattern 206 is a right angle, and the corner of the alignment mark frame pattern 206 is in contact with the right angle corner of the auxiliary alignment mark pattern 208 .

[0080] Specifically, the corners of the alignment mark frame graphic 206 are right angles, and the corners of the alignment mark frame graphic 206 are in contact with the right-angled corners of the auxiliary alignment mark graphic 208, so that the center point of the area enclosed by multiple auxiliary alignment mark graphics 208 can be consistent with the center point of the alignment mark frame graphic 206, and the corners of the alignment mark frame graphic 206 are in contact with the right-angled corners of the auxiliary alignment mark graphic 208. In the process of scanning and measuring the measurement mark graphic 210, the measuring instrument can easily identify the pattern with a right angle, thereby improving the measurement speed and saving measurement time.

[0081] There will be a fixed difference (AEI_ADIoffset) in the OVL value of the same measurement point from after development (ADI) to after etching (AEI). In order to obtain a fixed difference to correct ADI, it is necessary to design a post-etching measurement mark (AEI Mark) to obtain OVL.

[0082] As an example, the measurement mark pattern 210 is used to form a post-etching measurement mark.

[0083] In this embodiment, the measurement mark pattern 210 is in the first direction (eg Figure 7 X direction) and the second direction (as shown in Figure 7 The first direction and the second direction are symmetrical with each other, and the first direction and the second direction are perpendicular to each other.

[0084] Specifically, the measurement mark graphic 210 is used to form a measurement mark. In the process of scanning and measuring the measurement mark, the measurement mark needs to be measured once at 0° and 180°. By setting the measurement mark to be symmetrical in the first direction and the second direction, the measurement mark can be kept consistent at 0° and 180°. This means that in the process of scanning and measuring the measurement mark, only one angle between 0° and 180° needs to be selected to achieve the measurement of the measurement mark, thereby further improving the scanning rate of the measurement mark.

[0085] As an example, the measurement identification graphic 210 includes a measurement layer graphic (not marked) extending along the first direction and arranged in parallel and spaced apart along the second direction, so that the measurement layer graphic is symmetrical with each other in the first direction and the second direction. The measurement identification graphic 210 is used to form a measurement identification. Accordingly, in the process of scanning and measuring the measurement identification, only one angle between 0° and 180° needs to be selected to achieve the measurement of the measurement identification, thereby further improving the scanning rate of the measurement identification.

[0086] It should be noted that, in the process of scanning and measuring the measurement mark, it is necessary to find a right-angle pattern outside the measurement mark and input the right-angle coordinates. By setting auxiliary alignment marks at the corners of the alignment mark frame, and the auxiliary alignment marks all have right-angle corners, there is no need to find a right-angle pattern outside the measurement mark, but directly use the right-angle corners of the auxiliary alignment marks. Since the center point of the alignment mark frame, the center point of the measurement mark and the center point of the auxiliary alignment group coincide, it means that the vector distance between the measurement mark and the auxiliary mark group is zero. Accordingly, the measuring instrument does not need to be moved, and the measurement mark can be directly positioned through the center coordinate point of the alignment mark frame. The measurement mark can be directly scanned and the overlay error can be measured, thereby improving the speed and accuracy of scanning the measurement mark. At the same time, by using the right-angle corners of the auxiliary alignment mark, the influence of the right-angle pattern outside the measurement mark is reduced, so that the auxiliary alignment mark can be reused in different measurement environments, and only the center coordinate point of the alignment mark frame needs to be changed.

[0087] As an example, in the alignment mark frame pattern 206, a plurality of the auxiliary alignment mark patterns 208 are arranged in a first direction (eg Figure 7 X direction) and the second direction (as shown in Figure 7 The first direction and the second direction are symmetrical with each other, and the first direction and the second direction are perpendicular to each other.

[0088] Specifically, the plurality of auxiliary alignment mark graphics 208 are symmetrical with each other in the first direction and the second direction, and the first direction and the second direction are perpendicular to each other, so that the center point of the area enclosed by the plurality of auxiliary alignment mark graphics 208 coincides with the center point of the measurement mark graphic 210, which means that the vector distance between the measurement mark graphic 210 and the auxiliary mark group graphic is zero.

[0089] As an example, the shape of the auxiliary alignment mark pattern 208 includes one or more of a square, an L-shape, and a cross-shape.

[0090] It should be noted that the square, L-shaped and cross-shaped shapes all have right-angled corners. The measurement mark graphic 210 is used to form a measurement mark. In the process of scanning and measuring the measurement mark, the measuring instrument can easily identify patterns with right angles, thereby improving the measurement speed and saving measurement time. At the same time, the auxiliary alignment mark graphics 208 all have right-angled corners, so there is no need to look for right-angled patterns outside the alignment mark frame graphic 206. Instead, the right-angled corners of the auxiliary alignment mark graphic 208 are directly used. Since the center point of the alignment mark frame graphic 206, the center point of the measurement mark graphic 210 and the center point of the auxiliary alignment group graphic coincide with each other, it means that the vector distance between the measurement mark graphic 210 and the auxiliary mark group graphic is zero.

[0091] In this embodiment, the auxiliary alignment mark pattern 208 is a solid pattern.

[0092] Specifically, Figure 8 As shown, the shape of the auxiliary alignment mark pattern 208 includes one or more of a square, an L-shape, and a cross shape.

[0093] In other embodiments, the auxiliary alignment mark pattern includes a plurality of sub-auxiliary alignment mark patterns arranged at intervals, and the plurality of sub-auxiliary alignment mark patterns arranged at intervals constitute the auxiliary alignment mark pattern.

[0094] It should be noted that although the auxiliary alignment identification graphic 208 includes a plurality of sub-auxiliary alignment identification graphics 208 arranged at intervals, the overall outline of the auxiliary alignment identification graphic 208 composed of the plurality of sub-auxiliary alignment identification graphics 208 arranged at intervals has right-angle corners, so there is no need to look for a right-angle pattern outside the alignment identification frame graphic 206, but the right-angle corners of the auxiliary alignment identification graphic 208 can be directly used.

[0095] like Figures 9 to 11 As shown, the sub-auxiliary alignment mark pattern 208 includes a bar pattern or a through-hole pattern.

[0096] Specifically, Fig. 9 As shown, the auxiliary alignment mark pattern 208 includes a first direction (eg Fig. 9 X direction) and extends along the second direction (as shown in Fig. 9 The bar patterns are arranged at intervals (as shown in the Y direction), and some of the bar patterns are concave or convex inwardly relative to the remaining bar patterns.

[0097] like Fig.10 As shown, the auxiliary alignment mark pattern 208 includes a second direction (eg Fig.10 ) and extends along a first direction (as shown in the Y direction Fig.10 The strip patterns are arranged at intervals (as shown in the X direction), and some of the strip patterns are concave or convex inwardly relative to the remaining strip patterns.

[0098] like Fig.11 As shown, the auxiliary alignment mark includes a first direction (such as Fig.11 X direction) are arranged in parallel and spaced apart and along a second direction (as shown in Fig.11 A through-hole pattern arranged in parallel with intervals (as shown in the Y direction).

[0099] It should be noted that the distance between adjacent sub-auxiliary alignment mark patterns 208 should not be too small or too large. If the distance between the sub-auxiliary alignment mark patterns 208 is too small, the probability of the sub-auxiliary alignment mark patterns 208 overlapping each other is increased, and in the subsequent process of scanning and measuring the measurement mark, the accuracy of scanning the measurement mark and measuring the overlay error is reduced. If the distance between the sub-auxiliary alignment mark patterns 208 is too large, it is easy to cause the auxiliary mark group pattern to occupy too large an area, and excessively occupy the area of ​​the measurement mark pattern 210, and in the subsequent process of scanning and measuring the measurement mark, the difficulty of scanning the measurement mark and measuring the overlay error is increased. For this reason, in this embodiment, the distance between adjacent sub-auxiliary alignment mark patterns 208 is 35 nanometers to 2000 nanometers.

[0100] Correspondingly, an embodiment of the present invention further provides a measurement method. Fig.12 It is a flow chart of the steps of an embodiment of the testing method of the present invention.

[0101] refer to Fig.12 , execute step S1: provide a semiconductor structure provided by an embodiment of the present invention.

[0102] For a detailed description of the semiconductor structure provided by the embodiment of the present invention, please refer to the above description, which will not be repeated here.

[0103] refer to Fig.12 , execute step S2: obtain the center coordinate point of the alignment mark frame.

[0104] It should be noted that in the process of scanning and measuring the measurement mark, it is necessary to find a rectangular pattern outside the measurement mark and input the rectangular coordinates. By setting auxiliary alignment marks at the corners of the alignment mark frame, and the auxiliary alignment marks all have right-angle corners, there is no need to find a rectangular pattern outside the measurement mark, but the right-angle corners of the auxiliary alignment marks can be directly used.

[0105] It should also be noted that since the center point of the alignment mark frame, the center point of the measurement mark and the center point of the auxiliary alignment group coincide with each other, it means that the vector distance between the measurement mark and the auxiliary mark group is zero. Accordingly, the measuring instrument does not need to be moved, and the measurement mark can be directly positioned through the center coordinate point of the alignment mark frame, so that the measurement mark can be directly scanned and the overlay error can be measured, thereby improving the speed and accuracy of the measurement mark scanning. At the same time, by utilizing the right-angle corners of the auxiliary alignment mark, the influence of the right-angle pattern outside the alignment mark area is reduced, so that the auxiliary alignment mark can be reused in different measurement environments, and only the center coordinate point of the alignment mark frame needs to be changed.

[0106] Specifically, the center coordinate point of the alignment mark frame can be obtained by calculating the RFL file.

[0107] refer to Fig.12 , execute step S3: scan the measurement mark according to the center coordinate point, and calculate the overlay error value.

[0108] Specifically, the markings are measured by scanning electron microscopy.

[0109] It should be noted that in the process of scanning and measuring the measurement mark, the measurement mark needs to be measured once at 0° and 180°. Since the measurement mark is symmetrical in the first direction and the second direction, the measurement mark can be kept consistent at 0° and 180°. This means that in the process of scanning and measuring the measurement mark, only one angle needs to be selected between 0° and 180° to achieve the measurement of the measurement mark, thereby further improving the scanning rate of the measurement mark.

[0110] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A semiconductor structure, characterized in that: include: a substrate including an alignment mark area; an alignment mark frame, located in the base of the alignment mark area, the alignment mark frame having a corner; A measurement mark, located in the alignment mark frame; The auxiliary mark group includes a plurality of auxiliary alignment marks, wherein the auxiliary alignment marks are respectively located at the corners of the alignment mark frame, the auxiliary alignment marks have right-angle corners, and the center points of the alignment mark frame, the measurement mark and the auxiliary alignment group coincide with each other.

2. The semiconductor structure according to claim 1, wherein: The measurement marks are symmetrical in a first direction and a second direction, and the first direction and the second direction are perpendicular to each other.

3. The semiconductor structure according to claim 2, wherein: The measurement mark includes a measurement layer extending along a first direction and arranged in parallel and spaced relation along a second direction.

4. The semiconductor structure according to claim 1, wherein: In the alignment mark frame, the plurality of auxiliary alignment marks are symmetrical to each other in a first direction and a second direction, and the first direction and the second direction are perpendicular to each other.

5. The semiconductor structure according to claim 1, wherein: The alignment mark frame is in the shape of a square ring.

6. The semiconductor structure according to claim 1, wherein: The corner of the alignment mark frame is a right angle, and the corner of the alignment mark frame contacts the right angle corner of the auxiliary alignment mark.

7. The semiconductor structure according to claim 1, wherein: The auxiliary alignment mark may have a shape of one or more of a square, an L-shape, and a cross-shape.

8. The semiconductor structure according to claim 1 or 7, characterized in that: The auxiliary alignment mark is a solid pattern structure; or, The auxiliary alignment mark includes a plurality of sub-auxiliary alignment marks arranged at intervals, and the plurality of sub-auxiliary alignment marks arranged at intervals constitute the auxiliary alignment mark.

9. The semiconductor structure according to claim 8, characterized in that The sub-auxiliary alignment mark may be of a bar structure or a through-hole structure.

10. The semiconductor structure according to claim 8, wherein: The distance between adjacent sub-auxiliary alignment marks is 35 nanometers to 2000 nanometers.

11. A mask layout, characterized in that: include: An alignment mark frame graphic, wherein the alignment mark frame graphic has a corner; A measurement identification graphic, wherein the measurement identification graphic is located in the alignment identification frame graphic; An auxiliary mark group graphic, the auxiliary mark group graphic comprising a plurality of auxiliary alignment mark graphics, the auxiliary alignment mark graphics are respectively located at the corners of the alignment mark frame graphic, and the auxiliary alignment mark graphics have right-angle corners; Wherein, the center point of the alignment mark frame graphic, the center point of the measurement mark graphic and the center point of the auxiliary mark group coincide with each other.

12. The mask layout according to claim 11, characterized in that: The measurement mark pattern is symmetrical in a first direction and a second direction, and the first direction and the second direction are perpendicular to each other.

13. The mask layout according to claim 12, characterized in that: The measurement identification pattern includes measurement layer patterns extending along a first direction and arranged in parallel and spaced relation along a second direction.

14. The mask layout according to claim 11, characterized in that: The alignment mark frame graphic is in the shape of a square ring.

15. The mask layout according to claim 11, characterized in that: The corner of the alignment mark frame pattern is a right angle, and the corner of the alignment mark frame pattern contacts the right-angle corner of the auxiliary alignment mark pattern.

16. The mask layout according to claim 11, characterized in that: In the alignment mark frame pattern, the plurality of auxiliary alignment mark patterns are symmetrical to each other in a first direction and a second direction, and the first direction and the second direction are perpendicular to each other.

17. The mask layout according to claim 11, characterized in that: The auxiliary alignment mark pattern may have a shape of one or more of a square, an L-shape and a cross.

18. The mask layout according to claim 11 or 17, characterized in that: The auxiliary alignment mark pattern is a solid pattern; Alternatively, the auxiliary alignment mark pattern includes a plurality of sub-auxiliary alignment mark patterns arranged at intervals, and the plurality of sub-auxiliary alignment mark patterns arranged at intervals constitute the auxiliary alignment mark pattern.

19. The mask layout according to claim 18, characterized in that: The sub-auxiliary alignment mark pattern includes a bar pattern or a through-hole pattern.

20. A measurement method, characterized in that: include: Providing a semiconductor structure according to any one of claims 1 to 10; Obtaining the center coordinate point of the alignment mark frame; According to the central coordinate point, the measurement mark is scanned and the overlay error value is calculated.

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