Alignment mark and method for forming the same

Abstract

An alignment mark and a method for forming the same, wherein the alignment mark forming method comprises the following steps: after forming an alignment mark with a damaged portion on a substrate, a repair process is performed to form a repair layer, and the damaged portion of the alignment mark is repaired, so that the repaired alignment mark has no defects or even if there are defects, the defects are not large enough to affect alignment, so that when the repaired alignment mark is used as a new alignment mark for alignment, the alignment process can proceed smoothly while ensuring the accuracy of alignment.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and in particular to an alignment mark and a forming method thereof. Background Art

[0002] Photolithography is the main process in integrated circuit manufacturing. The task of the photolithography process is to transfer the pattern on the mask to the photoresist layer on the silicon wafer.

[0003] The photolithography process is generally carried out by a photolithography device. The existing photolithography device generally includes: a wafer stage for loading wafers; a mask stage located above the wafer stage and used for loading the mask; a light source located above the mask stage and used for providing exposure light; and an optical projection unit located between the mask stage and the wafer stage and used for projecting light passing through the mask onto the wafer.

[0004] When the prior art exposes the wafer, it is first necessary to divide the area on the wafer into exposure areas one by one, and then expose each exposure area in turn. In order to achieve accurate exposure of the wafer, it is very important to obtain the precise position information of the wafer (or the exposure area on the wafer) relative to the mask before exposing the wafer. The existing lithography device establishes the position relationship between the wafer stage, the wafer and the mask through the alignment step. The alignment includes wafer stage alignment, mask alignment and wafer alignment, wherein the wafer stage alignment can obtain the position information of the wafer stage in the coordinate system, the mask alignment can obtain the position information of the mask relative to the wafer stage, and the wafer alignment can obtain the position information of the wafer relative to the wafer stage. After the wafer stage alignment, mask alignment and wafer alignment, the position information of the wafer relative to the mask and the wafer stage can be established.

[0005] When performing wafer alignment, it is first necessary to form an alignment mark on the wafer, and then the alignment mark detection system detects the alignment mark on the wafer. When the alignment mark is obtained on the graphic sensor of the alignment mark detection system, the wafer alignment process is completed.

[0006] The existing alignment marks formed on the wafer are generally periodic patterns with protrusions and grooves. When detecting the alignment marks, the alignment marks are first illuminated, and the illumination light is diffracted at the alignment marks. The diffracted light is imaged on the graphic sensor of the alignment mark detection system, and then the image received on the graphic sensor is processed to realize the recognition of the alignment marks.

[0007] However, the prior art sometimes encounters problems such as being unable to perform alignment or having poor alignment accuracy when detecting alignment marks. Summary of the invention

[0008] The technical problem to be solved by the present invention is how to make the alignment process proceed smoothly and ensure the accuracy of the alignment.

[0009] The present invention provides a method for forming an alignment mark, comprising:

[0010] providing a substrate;

[0011] forming an alignment mark on the substrate, wherein the alignment mark has a damaged portion;

[0012] A repair process is performed to form a repair layer, the damaged portion of the alignment mark is repaired, and the repaired alignment mark is used as a new alignment mark.

[0013] Optionally, the alignment mark with the damaged portion includes a plurality of parallel protrusions and grooves located between adjacent protrusions, and the damaged portion refers to at least one protrusion having one or more of the following defects: surface depression defect, side wall unevenness defect, size defect or tilt defect.

[0014] Optionally, the repair process includes: forming a repair material layer on the substrate, the repair material layer covering the alignment mark with damage; etching and removing unnecessary repair material layer to form a repair layer, and the repair layer repairs the damaged portion of the alignment mark.

[0015] Optionally, after forming the repair material layer on the substrate, it also includes: forming a mask layer pattern on the repair material layer, the shape and position of the mask layer pattern correspond to the shape and position of the alignment mark where there is no damage; using the mask layer pattern as a mask, etching and removing unnecessary repair material layer.

[0016] The present invention also provides an alignment mark, comprising:

[0017] substrate;

[0018] an alignment mark on the substrate, wherein the alignment mark has a damaged portion;

[0019] A repairing layer is used to repair the damaged part of the alignment mark, and the alignment mark with the repairing layer is used as a new alignment mark.

[0020] Optionally, the alignment mark with the damaged portion includes a plurality of parallel protrusions and grooves located between adjacent protrusions, and the damaged portion refers to at least one protrusion having one or more of the following defects: surface depression defect, side wall unevenness defect, size defect or tilt defect.

[0021] The present invention also provides a method for forming an alignment mark, comprising:

[0022] providing a substrate;

[0023] forming an alignment mark on the substrate, wherein the alignment mark has a damaged portion;

[0024] forming a mask material layer on the substrate, wherein the mask material layer covers the alignment mark at the damaged location;

[0025] The mask material layer is etched to form a new alignment mark on the alignment mark with the damage.

[0026] Optionally, the alignment mark at the damaged location includes a plurality of parallel protrusions and grooves located between adjacent protrusions; the mask material layer fills the grooves of the alignment mark, and the surface of the mask material layer is higher than the top surface of the alignment mark at the damaged location; the portion of the mask material layer on the top surface of the alignment mark at the damaged location is etched to form a new alignment mark.

[0027] Optionally, before forming the mask material layer on the substrate, an etch stop layer is formed on the substrate, and then the mask material layer is formed on the etch stop layer.

[0028] Optionally, the new alignment mark is located above the protrusion and the groove of the alignment mark with the damaged portion, or the new alignment mark is located only above the protrusion of the alignment mark with the damaged portion.

[0029] Optionally, the new alignment mark and the alignment mark with the damaged portion are alignment marks of the same type or alignment marks of different types.

[0030] The present invention also provides an alignment mark, comprising:

[0031] substrate;

[0032] an alignment mark located on the substrate, wherein the alignment mark has a damaged portion;

[0033] A new alignment mark is located on the alignment mark where the damage exists.

[0034] Optionally, the alignment mark with the damaged portion includes a plurality of parallel protrusions and grooves between adjacent protrusions; and the grooves are filled with a filling layer.

[0035] Optionally, the new alignment mark is located above the protrusion, the groove and the filling layer of the alignment mark with the damaged part, or the new alignment mark is located only above the protrusion of the alignment mark with the damaged part.

[0036] Optionally, the new alignment mark and the alignment mark with the damaged portion are alignment marks of the same type or alignment marks of different types.

[0037] Optionally, an etch stop layer is provided between the new alignment mark and the alignment mark with the damaged portion.

[0038] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0039] The method for forming an alignment mark of the present invention performs a repair process to form a repair layer, and repairs the damaged part of the alignment mark so that the repaired alignment mark has no defects or even if there are defects, the defects are not sufficient to affect the alignment. Therefore, when the repaired alignment mark is used as a new alignment mark for alignment, the alignment process can proceed smoothly while ensuring the accuracy of the alignment.

[0040] At the same time, since the repaired alignment mark does not change the position, type and shape of the alignment mark, the existing alignment method and alignment process can still be used without changing the existing process flow, saving costs and improving efficiency.

[0041] Furthermore, the repair material layer is made of the same material as the alignment mark, so that the subsequently formed repair layer is consistent with the material of the alignment mark, and thus the repaired alignment mark is basically consistent with the alignment mark without defects, so that the alignment process can proceed smoothly while ensuring the accuracy of alignment, and the repair process is simple; in addition, since the repaired alignment mark does not change the material, position, type and shape of the alignment mark, the existing alignment method and alignment process can still be used without changing the existing process flow, saving costs and improving efficiency.

[0042] Furthermore, after the repair material layer is formed on the substrate, the method further comprises: forming a mask layer pattern on the repair material layer, wherein the shape and position of the mask layer pattern correspond to the shape and position of the alignment mark at the non-damaged portion. The purpose of forming the mask layer pattern is to ensure that when the unnecessary repair material layer is removed, the remaining repair material layer (repair layer) just repairs the damaged portion of the alignment mark, so that the repaired alignment mark is consistent with the alignment mark at the non-damaged portion.

[0043] The alignment mark of the present invention comprises a repairing layer, and the damaged part of the alignment mark is repaired, and the alignment mark with the repairing layer is used as a new alignment mark, so that the alignment process can be carried out smoothly and the alignment accuracy is guaranteed.

[0044] The method for forming an alignment mark of the present invention comprises forming a mask material layer on the substrate, wherein the mask material layer covers the alignment mark at the damaged location; etching the mask material layer to form a new alignment mark on the alignment mark at the damaged location. By forming a new alignment mark on the alignment mark at the damaged location, the new alignment mark is used as the alignment mark during subsequent alignment, thereby preventing the problem of inability to align and alignment accuracy when using the alignment mark at the damaged location for alignment.

[0045] Furthermore, the portion of the mask material layer on the top surface of the alignment mark where the damage exists is etched to form a new alignment mark, that is, the formed new alignment mark corresponds to the protrusion and groove above the alignment mark where the damage exists, so the new alignment mark does not occupy an additional lateral area of ​​the wafer. Moreover, the new alignment mark is of the same type as the alignment mark where the damage exists, and the new alignment mark not only does not occupy an additional lateral area of ​​the wafer, but also makes the alignment process more convenient, and because the new alignment mark corresponds to the same type as the alignment mark where the damage exists, the existing alignment method and alignment process can still be used, without changing the existing process flow, saving costs and improving efficiency.

[0046] Furthermore, before forming the mask material layer on the substrate, an etch stop layer is formed on the substrate. The purpose of forming the etch stop layer is, on the one hand, to protect the semiconductor device formed in the device area from being damaged when a portion of the mask material layer is subsequently etched away, and on the other hand, when a new alignment mark is formed on the alignment mark with damage, the etch stop layer is used as the stop layer when etching the mask material layer, so that the new alignment mark can be formed just on the protrusion of the alignment mark with damage. The formed new alignment mark has high position accuracy and high morphology. When the new alignment mark is separated from the alignment mark with damage by the etch stop layer, there is an obvious distinguishing interface between the new alignment mark and the alignment mark with damage. When the new alignment mark is subsequently aligned and calibrated, the interference of the alignment mark with damage on the detection of the new alignment mark can be prevented or reduced.

[0047] The alignment mark of the present invention includes a new alignment mark located on the alignment mark at the damaged location. The new alignment mark is used as the alignment mark during alignment, thereby preventing the problem of misalignment and alignment accuracy when the damaged alignment mark is used for alignment. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1-5 is a schematic diagram of a method for forming an alignment mark in one embodiment of the present invention;

[0049] Figure 6-8 is a schematic diagram of a method for forming an alignment mark according to another embodiment of the present invention;

[0050] Figure 9-13 FIG. 4 is a schematic diagram of a method for forming an alignment mark according to another embodiment of the present invention. DETAILED DESCRIPTION

[0051] As mentioned in the background art, the prior art often encounters the problem of being unable to align or having poor alignment accuracy when detecting alignment marks.

[0052] Research has found that existing alignment marks are usually periodic patterns with protrusions and grooves, and alignment marks are generally formed by photolithography and etching processes. In the actual formation process, due to the deviation of the photolithography and etching process, fluctuations in equipment stability, defects or other factors, the formed alignment marks may have damages, and the damage is specifically manifested as one or more of surface depression defects, sidewall unevenness defects, size defects or tilt defects in at least one protrusion in the alignment mark. When detecting the alignment mark with damages, the equipment cannot recognize the alignment mark with damages, and thus cannot perform alignment, or even if the equipment can recognize the alignment mark, the diffraction light generated by the alignment mark has deviations due to the presence of damages, making it difficult to ensure the accuracy of alignment.

[0053] In addition, if the wafer is reworked and the alignment marks are remade, the process cost will inevitably increase and the device area that has been formed will be adversely affected.

[0054] To this end, the present invention provides an alignment mark and a method for forming the same, wherein the alignment mark forming method comprises the following steps: after forming an alignment mark with a damaged portion on a substrate, a repair process is performed to form a repair layer, and the damaged portion of the alignment mark is repaired, so that the repaired alignment mark has no defects or even if there are defects, the defects are not sufficient to affect the alignment, and thus when the repaired alignment mark is used as a new alignment mark for alignment, the alignment process can proceed smoothly while ensuring the accuracy of the alignment.

[0055] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. When describing the embodiments of the present invention in detail, for the sake of convenience, the schematic diagrams will not be partially enlarged according to the general proportion, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0056] Figure 1-5 FIG. 4 is a schematic diagram of a method for forming an alignment mark according to an embodiment of the present invention.

[0057] Please refer to Figure 1 , providing a substrate 201; forming an alignment mark 21 on the substrate 201, wherein the alignment mark 21 has a damaged portion (22, 23).

[0058] In this embodiment, the base 201 is a semiconductor substrate, and the material of the semiconductor substrate can be silicon (Si), germanium (Ge), or silicon germanium (GeSi), silicon carbide (SiC); it can also be silicon on insulator (SOI), germanium on insulator (GOI); or it can also be other materials, such as III-V group compounds such as gallium arsenide. In one embodiment, the alignment mark 21 is formed by etching the semiconductor substrate, or by forming a material layer on the semiconductor substrate and then etching the material layer.

[0059] In other embodiments of the present invention, the base 201 includes a semiconductor substrate and a dielectric layer on the semiconductor substrate, and the alignment mark 21 is formed on the dielectric layer. In one embodiment, the alignment mark 21 is formed by forming a material layer on the dielectric layer and then etching the material layer.

[0060] In one embodiment, the substrate 201 may include a scribe line region and a device region between the scribe line regions, and the alignment mark 21 is formed on the scribe line region of the substrate 201 .

[0061] The formed alignment mark 21 is an alignment mark used for aligning the wafer and the wafer stage, and the wafer and the mask during the photolithography process. In this embodiment, since the formed alignment mark 21 is damaged, there is a problem of being unable to align or inaccurately aligning during alignment.

[0062] The alignment mark 21 with the damaged part includes a plurality of parallel protrusions 202 and grooves 203 between adjacent protrusions 202. The damaged part refers to at least one protrusion 202 having one or more of surface depression defects, sidewall unevenness defects, size defects or tilt defects. The presence of the damaged part will affect the alignment and the accuracy of the alignment. It should be noted that the damaged part can be other defects that will affect the alignment.

[0063] In this embodiment, the alignment mark 21 is described as an example having four protrusions 202 and three grooves 203. In other embodiments, the number of protrusions and grooves in the alignment mark 21 can be other numbers, such as 2 protrusions and 1 groove, or 3 protrusions and 2 grooves.

[0064] In this embodiment, reference Figure 1, taking the damaged part as an alignment mark 21 in which a protrusion 202 has a surface depression defect 22 or a protrusion 202 has a size defect 23 as an example. The depression defect 22 refers to the lack of one or more pieces on the surface (top and / or side wall surface) of the protrusion 202, making the protrusion 202 incomplete. The size defect 23 refers to the abnormality in the width of the protrusion 23, specifically, the width of the protrusion 23 is greater than or less than the set width. The sidewall unevenness defect refers to the sidewall of the protrusion 23 being uneven or having a low flatness. The tilt defect refers to the sidewall of the protrusion 23 being tilted in a certain direction.

[0065] Combined with reference Figure 2-Figure 5 , a repair process is performed to form a repair layer 206, the damaged portion of the alignment mark 21 is repaired, and the repaired alignment mark 21 is used as a new alignment mark.

[0066] In this embodiment, a repair layer 206 is formed through a repair process to repair the damaged part of the alignment mark 21, so that the repaired alignment mark has no defects or even if there are defects, the defects are not enough to affect the alignment. Therefore, when the repaired alignment mark is used as a new alignment mark for alignment, the alignment process can proceed smoothly while ensuring the accuracy of alignment. At the same time, since the repaired alignment mark does not change the position, type and shape of the alignment mark, the existing alignment method and alignment process can still be used without changing the existing process flow, saving costs and improving efficiency.

[0067] In one embodiment, the repair process includes: forming a repair material layer 204 (see Figure 2 ), the repair material layer 204 covers the alignment mark 21 where the damage exists; the unnecessary repair material layer is removed by etching to form a repair layer 206 (refer to Figure 4 ), the repair layer 206 repairs the damaged portion of the alignment mark 21.

[0068] For details, please refer to Figure 2 , a repair material layer 204 is formed on the substrate 201, the repair material layer 204 covers the alignment mark 21 with the damage, and the repair material layer 204 has a flat surface. For example, the repair material layer 204 can be a spin-on carbon layer (SOC), or a spin-on glass layer (SOG) or other spin-on material layer, so that the formed repair material layer 204 has a flat surface.

[0069] Optionally, the repair material layer 204 may also be formed by a chemical vapor deposition process (CVD) and a planarization process.

[0070] In the present embodiment, the repair material layer 204 is made of the same material as the alignment mark 21, so that the subsequently formed repair layer is consistent with the material of the alignment mark 21, and thus the repaired alignment mark 21 is substantially consistent with the alignment mark without defects, so that the alignment process can proceed smoothly while ensuring the alignment accuracy, and the repair process is simple; in addition, since the repaired alignment mark does not change the material, position, type and shape of the alignment mark, the existing alignment method and alignment process can still be used without changing the existing process flow, thereby saving costs and improving efficiency.

[0071] In one embodiment, the materials of the repair material layer 204 and the alignment mark 21 are both silicon or silicon nitride.

[0072] It should be noted that, in other embodiments, the repair material layer 204 and the alignment mark 21 may be made of different materials.

[0073] Please refer to Figure 3 After forming a repair material layer 204 on the substrate 201, the method further includes: forming a mask layer pattern 205 on the repair material layer 204, wherein the shape and position of the mask layer pattern 205 correspond to the shape and position of the alignment mark 21 where there is no damage.

[0074] The purpose of forming the mask layer pattern 205 is to ensure that when the unnecessary repair material layer is removed, the remaining repair material layer (repair layer) just repairs the damaged part of the alignment mark 21, so that the repaired alignment mark is consistent with the alignment mark of the non-existent damaged part.

[0075] The shape and position of the mask layer pattern 205 correspond to the shape and position of the alignment mark 21 without damage, which means that the shape of the mask layer pattern 205 is the same as the shape of the alignment mark 21 without damage, such as the width of the mask layer pattern 205 and the alignment mark 21 are both 1um. The position of the mask layer pattern 205 is located directly above the alignment mark 21 without damage.

[0076] In one embodiment, the material of the mask layer pattern 205 is photoresist, and the mask layer pattern 205 is formed by spin coating, exposure and development processes.

[0077] Please refer to Figure 4 Using the mask layer pattern 205 as a mask, the unnecessary repair material layer is removed by etching to form a repair layer 206 , and the repair layer 206 is used to repair the damaged portion of the alignment mark 21 .

[0078] An anisotropic dry etching process is used to etch away the unnecessary repair material layer. In one embodiment, the anisotropic dry etching process is a plasma etching process, so that the formed repair layer 206 can accurately repair the damaged part.

[0079] The repair layer 206 can be used to repair Figure 4 The recessed defect 22 in the alignment mark 21 can be removed, and when removing the unnecessary repair material layer, the wider part (corresponding to repairing the size defect) and the inclined part (corresponding to repairing the inclined defect) in the alignment mark 21 can be removed at the same time, so that the repaired alignment mark 21 has no defects.

[0080] In one embodiment, when the repair layer 206 is formed, the mask layer pattern 205 is removed simultaneously.

[0081] In other embodiments, reference Figure 5 After forming the repair layer 206, the mask layer pattern 205 is removed by an etching process.

[0082] The embodiment of the present invention also provides an alignment mark, please refer to Figure 5 ,include:

[0083] Base 201;

[0084] An alignment mark 21 located on the substrate 201, wherein the alignment mark 21 has a damaged portion;

[0085] The repair layer 206 is used to repair the damaged portion of the alignment mark 21 , and the alignment mark 21 with the repair layer 206 is used as a new alignment mark.

[0086] Specifically, the alignment mark 21 with damage includes a plurality of parallel protrusions 202 and grooves 203 located between adjacent protrusions 202, and the damage means that at least one protrusion 203 has one or more of surface depression defects, side wall unevenness defects, size defects or tilt defects.

[0087] In this embodiment, the material of the repair layer 206 is consistent with the material of the alignment mark 21 where the damage occurs.

[0088] Figure 6-8 It is a schematic diagram of a method for forming an alignment mark in another embodiment of the present invention. It should be noted that the definitions or descriptions of the same or similar structures in this embodiment and the previous embodiment are not repeated in this embodiment, and please refer to the definitions or descriptions of the corresponding parts in the previous embodiment for details.

[0089] refer to Figure 6, providing a substrate 201; forming an alignment mark on the substrate 201, wherein the alignment mark 21 has a damaged portion; forming a mask material layer 210 on the substrate 201, wherein the mask material layer 210 covers the alignment mark 21 having a damaged portion.

[0090] In one embodiment, the mask material layer 210 is made of silicon nitride, metal nitride or other suitable materials.

[0091] The alignment mark 21 with the damaged part (22, 23) includes a plurality of parallel protrusions 202 and grooves between adjacent protrusions; the formed mask material layer 210 covers the alignment mark with the damaged part, the mask material layer 210 fills the groove of the alignment mark, and the surface of the mask material layer 210 is higher than the top surface of the alignment mark 21 with the damaged part, and the mask material layer 210 has a flat surface. In one embodiment, the mask material layer 210 is formed by a chemical vapor deposition process and a flattening process.

[0092] refer to Figure 7 , etching the mask material layer 210 (refer to Figure 6 ), forming a new alignment mark 32 on the alignment mark 21 where the damage exists.

[0093] In one embodiment, before etching the mask material layer 210, a patterned photoresist layer is formed on the surface of the mask material layer 210; the mask material layer 210 is etched using the patterned photoresist layer as a mask to form a new alignment mark 32 on the alignment mark 21 where the damage exists.

[0094] In this embodiment, the portion of the mask material layer 210 on the top surface of the alignment mark 21 with the damage is etched to form a new alignment mark 32, that is, the formed new alignment mark 32 is located above the protrusion and groove of the alignment mark 21 with the damage, so the new alignment mark 32 does not occupy an additional lateral area of ​​the wafer. In this embodiment, by forming a new alignment mark 32 on the alignment mark 21 with the damage, the new alignment mark 32 is used as the alignment mark during subsequent alignment, thereby preventing the problem of alignment failure and alignment accuracy when using the alignment mark 21 with the damage for alignment.

[0095] After forming a new alignment mark 32 , the remaining portion of the mask material layer in the groove of the alignment mark 21 with the damage and on the substrate 201 serves as a filling layer 211 .

[0096] The new alignment mark 32 and the alignment mark 21 with the damage may be of the same type or different types.

[0097] In one embodiment, reference Figure 7 , the new alignment mark 32 and the alignment mark 21 with the damaged part are different types of alignment marks. Different types of alignment marks mean that the new alignment mark 32 and the alignment mark 21 with the damaged part are different in the number of protrusions and grooves and / or the characteristic sizes of the protrusions and grooves.

[0098] Figure 7 The type of the alignment mark 21 with damage is AH74 (the total number of protrusions and grooves is 7, and the number of protrusions is 4), and the type of the new alignment mark 32 is AH32 (the total number of protrusions and grooves is 3, and the number of protrusions is 2).

[0099] In other embodiments, the type of the new alignment mark 32 may also be AH74 or AH53.

[0100] In another embodiment, reference Figure 8 , the new alignment mark 32 is of the same type as the alignment mark 21 with the damaged portion. The same type of alignment mark means that the new alignment mark 32 and the alignment mark 21 with the damaged portion have the same number of protrusions and grooves and the same characteristic sizes of the protrusions and grooves.

[0101] refer to Figure 8 The new alignment mark 32 and the alignment mark 21 with damage are both of type AH74.

[0102] In the present embodiment, the new alignment mark 32 is of the same type as the alignment mark 21 with the damaged portion. Not only does the new alignment mark 32 not occupy additional lateral area of ​​the wafer, but also because the new alignment mark 32 corresponds to the same type as the alignment mark 21 with the damaged portion, the existing alignment method and alignment process can still be used without changing the existing process flow, thereby saving costs and improving efficiency.

[0103] Figure 9-13 It is a schematic diagram of a method for forming an alignment mark in another embodiment of the present invention. It should be noted that the definitions or descriptions of the same or similar structures in this embodiment and the previous embodiment are not repeated in this embodiment, and please refer to the definitions or descriptions of the corresponding parts in the previous embodiment for details.

[0104] refer to Fig. 9 , providing a substrate 201; forming an alignment mark 21 on the substrate 201, wherein the alignment mark 21 has a damaged portion.

[0105] In this embodiment, the substrate 201 includes an alignment mark area 11 and a device area 12. The alignment mark area 11 is used to form an alignment mark, and a semiconductor device is formed on the device area 12. The semiconductor device may include a transistor, a memory, a sensor, an edgeless device, and a related dielectric layer and a metal line located in the dielectric layer.

[0106] refer to Fig.10 and Fig.11 Before forming a mask material layer on the substrate 201, an etch stop layer 209 is formed on the substrate 201, and then a mask material layer 210 is formed on the etch stop layer 209, wherein the mask material layer 210 has a flat surface, and the surface of the mask material layer 210 is higher than the surface of the etch stop layer 209.

[0107] The purpose of forming the etch stop layer 209 is, on the one hand, to protect the semiconductor device formed in the device 12 area from being damaged when a portion of the mask material layer 210 is subsequently etched away; on the other hand, when a new alignment mark is formed on the alignment mark 21 with a damage, the etch stop layer 209 is used as a stop layer for etching the mask material layer 210, so that the new alignment mark can be formed just on the protrusion of the alignment mark 21 with a damage. The formed new alignment mark has high position accuracy and high morphology. When the new alignment mark is separated from the alignment mark 21 with a damage by the etch stop layer, there is an obvious distinguishing interface between the new alignment mark and the alignment mark 21 with a damage. When the new alignment mark is subsequently aligned and calibrated, the interference of the alignment mark 21 with the damage on the detection of the new alignment mark can be prevented or reduced.

[0108] In one embodiment, the material of the etch stop layer 209 is different from the material of the new alignment mark and the material of the alignment mark 21 with damage.

[0109] refer to Fig.12 , the mask material layer 210 except above the alignment mark 21 is removed.

[0110] When the mask material layer 210 other than the portion above the alignment mark 21 is removed, the etch stop layer other than the portion above the alignment mark 21 may be removed simultaneously.

[0111] In other embodiments, the mask material layer 210 and the etch stop layer other than those above the alignment mark 21 may also be removed after forming a new alignment mark.

[0112] refer to Fig.13 , etching the mask material layer 210 on the alignment mark 21 to form a new alignment mark 32.

[0113] In this embodiment, the new alignment mark 32 is formed above the protrusion 202 of the alignment mark 21 with a damaged portion.

[0114] The embodiment of the present invention also provides an alignment mark, please refer to Figure 7 or Figure 8 or Fig.13 ,include:

[0115] Base 201;

[0116] An alignment mark 21 located on the substrate 201, wherein the alignment mark 21 has a damaged portion;

[0117] A new alignment mark 32 is located on the alignment mark 21 where the damage exists.

[0118] Specifically, the alignment mark 21 with damage includes a plurality of parallel protrusions 202 and grooves between adjacent protrusions 202; the grooves are filled with a filling layer 211.

[0119] The new alignment mark 32 is located above the protrusion, groove and filling layer of the alignment mark 21 where the damage exists (refer to Figure 7 or Figure 8 ), or the new alignment mark 32 is located only above the protrusion of the alignment mark 21 where the damage exists (refer to Fig.13 ).

[0120] The new alignment mark 32 and the alignment mark 31 with the damage may be of the same type or different types.

[0121] The type of the new alignment mark 32 is AH32, AH53 or AH74.

[0122] In one embodiment, an etch stop layer 209 is provided between the new alignment mark 32 and the alignment mark 21 with damage.

[0123] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for forming an alignment mark, It is characterized in that include: Providing a substrate, the substrate comprising an alignment mark area and a device area; forming an alignment mark in an alignment mark region on the substrate, wherein the alignment mark has a damaged portion; forming an etch stop layer on the substrate, wherein the etch stop layer covers the device region and the alignment mark where the damage exists; forming a mask material layer on the etch stop layer; Etching the mask material layer to form a new alignment mark on the alignment mark with the damage; The etch stop layer is removed except for the alignment mark where the damage exists.

2. The method for forming an alignment mark according to claim 1, It is characterized in that The new alignment mark and the alignment mark with the damaged portion are alignment marks of the same type or alignment marks of different types.

3. An alignment mark, It is characterized in that include: A substrate, the substrate comprising an alignment mark area and a device area; an alignment mark located in an alignment mark area on the substrate, wherein the alignment mark has a damaged portion; A new alignment mark is located on the alignment mark where the damage exists, an etch stop layer is provided between the new alignment mark and the alignment mark where the damage exists, and the etch stop layer is only located above the alignment mark where the damage exists.

4. The alignment mark according to claim 3, It is characterized in that The alignment mark with the damaged part comprises a plurality of parallel protrusions and grooves between adjacent protrusions; the grooves are filled with a filling layer.

5. The alignment mark according to claim 3, It is characterized in that The new alignment mark and the alignment mark with the damaged portion are alignment marks of the same type or alignment marks of different types.

6. The alignment mark according to claim 3, It is characterized in that The alignment mark with the damaged part includes a plurality of parallel protrusions and grooves between adjacent protrusions, and the damaged part refers to at least one protrusion having one or more of the following defects: surface depression defect, side wall unevenness defect, size defect or tilt defect.

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