Positioning mark group, mask group and photoetching method

Abstract

The invention discloses a positioning mark group, a mask group and a photoetching method, and the positioning mark group comprises a first positioning mark which comprises a first positioning pattern area and a first blank area; the second positioning mark comprises a second positioning pattern area and a second blank area; when the first positioning mark and the second positioning mark are aligned, the first positioning graph and the second positioning graph are spliced, the first positioning graph area is aligned and overlapped with at least part of the second blank area, and the second positioning graph area is aligned and overlapped with at least part of the first blank area. Different masks in the mask set, the positioning patterns based on the positioning pattern areas and the blank areas are spliced, the positions of the positioning marks in the positioning mark groups on the masks are freely arranged, the limitation of the arrangement positions of the positioning marks on the masks can be broken through, the limitation of the exposure sequence can be broken through, errors can be effectively reduced, and the accuracy of the mask set is improved. The process window can be expanded, and the process difficulty can be reduced.

Description

Technical Field

[0001] The invention relates to the field of semiconductor manufacturing, and in particular to a positioning mark group, a mask group and a photolithography method. Background Art

[0002] With the continuous development of integrated circuit manufacturing technology, people's requirements for the integration and performance of integrated circuits are becoming higher and higher. In order to improve integration and reduce costs, the key dimensions of components are constantly decreasing, and the circuit density inside the integrated circuit is increasing.

[0003] In the integrated circuit manufacturing process, photolithography technology is usually used to manufacture semiconductor devices. Through projection, development and other processes, the pattern on the mask is transferred to the semiconductor material, and through etching, deposition and other processes, diodes, transistors, resistors, capacitors and other components and their connections are formed.

[0004] When making a chip whose size exceeds the maximum exposure area, it is necessary to use a splicing mask for lithography, and through multiple exposures to splice the pattern and complete the production of a large-size chip. However, in the existing splicing mask set, the setting position of the positioning mark points on the mask is highly restricted; and when performing lithography, there are strict exposure sequence restrictions between different masks. Different positioning mark setting positions and different exposure sequences may cause the positioning marks to be unable to be spliced, thereby affecting the subsequent process. Summary of the invention

[0005] The problem solved by the present invention is how to break through the limitation of the location of the positioning mark and the limitation of the exposure sequence, and reduce the difficulty of aligning the splicing mask.

[0006] In order to solve the above problems, the present invention provides a positioning mark set, comprising:

[0007] A first positioning mark, the first positioning mark is configured to be set on the first mask, the first positioning mark includes: a first positioning pattern area and a first blank area, the first positioning pattern area has a first positioning pattern, and the first blank area has no pattern; a second positioning mark, the second positioning mark is configured to be set on the second mask, the second positioning mark includes: a second positioning pattern area and a second blank area, the second positioning pattern area has a second positioning pattern, and the second blank area has no pattern; the first positioning mark and the second positioning mark are relatively aligned to achieve the splicing of the pattern of the first mask and the pattern of the second mask; when the first positioning mark and the second positioning mark are relatively aligned, the first positioning pattern and the second positioning pattern are spliced, and the first positioning pattern area is aligned and overlapped with at least a portion of the second blank area, and the second positioning pattern area is aligned and overlapped with at least a portion of the first blank area.

[0008] Optionally, different positioning marks are relatively punctual, and the corresponding positioning graphics do not overlap.

[0009] Optionally, the positioning pattern includes: an internal sub-pattern and a peripheral sub-pattern, the internal sub-pattern is located between the peripheral sub-pattern and the blank area, and the positioning pattern is one of the first positioning pattern and the second positioning pattern.

[0010] Optionally, the positioning mark includes: a positioning point, the position of which is used to achieve position alignment between the positioning marks; and the positioning mark is one of the first positioning mark and the second positioning mark.

[0011] Optionally, the positioning point is the geometric center of a figure obtained by splicing the first positioning figure and the second positioning figure.

[0012] Optionally, it also includes: a third positioning mark, the third positioning mark is configured to be set on the third mask, the third positioning mark includes: a third positioning pattern area and a third blank area, the third positioning pattern area has a third positioning pattern, and the third blank area has no pattern; the first positioning mark, the second positioning mark and the third positioning mark are relatively aligned to achieve splicing of the pattern of the first mask, the pattern of the second mask and the pattern of the third mask; when the first positioning mark, the second positioning mark and the third positioning mark are relatively aligned, the first positioning pattern, the second positioning pattern and the third positioning pattern are spliced, and the first positioning pattern area and the second positioning pattern area are aligned and overlapped with at least part of the third blank area, the second positioning pattern area and the third positioning pattern area are aligned and overlapped with at least part of the first blank area, and the third positioning pattern area and the first positioning pattern area are aligned and overlapped with at least part of the second blank area.

[0013] Optionally, it also includes: a fourth positioning mark, the fourth positioning mark is configured to be set on the fourth mask, the fourth positioning mark includes: a fourth positioning pattern area and a fourth blank area, the fourth positioning pattern area has a fourth positioning pattern, and the fourth blank area does not have a pattern; the first positioning mark, the second positioning mark, the third positioning mark and the fourth positioning mark are relatively aligned to achieve the splicing of the pattern of the first mask, the pattern of the second mask, the pattern of the third mask and the pattern of the fourth mask; when the first positioning mark, the second positioning mark, the third positioning mark and the fourth positioning mark are relatively aligned, the first positioning pattern, the second positioning pattern, the third positioning pattern and the fourth positioning pattern are spliced, and the first positioning pattern area, the second positioning pattern area and the third positioning pattern area are aligned and overlapped with the fourth blank area; the second positioning pattern area, the third positioning pattern area and the fourth positioning pattern area are aligned and overlapped with the first blank area; the third positioning pattern area, the fourth positioning pattern area and the first positioning pattern area are aligned and overlapped with the second blank area; the fourth positioning pattern area, the first positioning pattern area and the second positioning pattern area are aligned and overlapped with the third blank area.

[0014] Accordingly, the present invention further provides a mask set, comprising:

[0015] A first mask, wherein the first mask has a first positioning mark group, and the first positioning mark group is the positioning mark group of the present invention; a second mask, wherein the second mask has a second positioning mark group, and the second positioning mark group is the positioning mark group of the present invention; the distribution positions of the positioning marks in the first positioning mark group correspond to the distribution positions of the positioning marks in the second positioning mark group.

[0016] Optionally, the mask has a splicing area and a non-splicing area; the positioning mark is located in the splicing area, wherein the mask is one of the first mask and the second mask, and the positioning mark is a positioning mark on the mask.

[0017] Optionally, it also includes: a third mask, the third mask having a third positioning mark group, the third positioning mark group being the third positioning mark of the positioning mark group provided by the present invention; the distribution positions of the positioning marks in the first positioning mark group, the distribution positions of the positioning marks in the second positioning mark group and the distribution positions of the positioning marks in the third positioning mark group correspond to each other.

[0018] Optionally, it also includes: a fourth mask, the fourth mask having a fourth positioning mark group, the fourth positioning mark group being the fourth positioning mark of the positioning mark group provided by the present invention; the distribution positions of the positioning marks in the first positioning mark group, the distribution positions of the positioning marks in the second positioning mark group, the distribution positions of the positioning marks in the third positioning mark group and the distribution positions of the positioning marks in the fourth positioning mark group correspond to each other.

[0019] Optionally, the positioning mark is located at a top corner of the mask, wherein the positioning mark is one of the first positioning mark, the second positioning mark, the third positioning mark and the fourth positioning mark, and the mask is a mask corresponding to the positioning mark.

[0020] In addition, the present invention also provides a photolithography method, which uses the mask group of the present invention to perform photolithography, including: providing a substrate, on which there is a material layer to be processed; using a first mask to pattern the material layer to be processed to form a first pattern layer; using a second mask to pattern the first pattern layer to form a second pattern layer.

[0021] Optionally, the step of patterning the first pattern layer using a second mask includes: aligning according to positions of positioning points of positioning marks in a second positioning mark group possessed by the second mask.

[0022] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0023] In the positioning mark group of the present invention, each positioning mark includes a positioning pattern area with a positioning pattern and a blank area without a pattern; when different positioning marks are aligned, the positioning patterns of different positioning marks are spliced, and the positioning pattern areas of different positioning marks are at least partially aligned and overlapped with the blank area; it can be seen that different masks in the mask group of the present invention are spliced ​​based on the positioning patterns and blank areas of the positioning pattern area, and the positions of the positioning marks in the positioning mark group on the mask are freely set, which can break through the restrictions on the positions of the positioning marks on the mask, can break through the restrictions on the exposure sequence, can effectively reduce errors, and are conducive to the expansion of the process window and the reduction of process difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a positioning mark for the splicing mask set;

[0025] Figure 2 It is a schematic diagram of the positioning mark formed by the wrong exposure sequence;

[0026] Figure 3 is a schematic diagram of the splicing graphics of some embodiments of the positioning mark set of the present invention;

[0027] Figures 4 to 7 is a schematic diagram of the structure of each positioning mark of some embodiments of the positioning mark set of the present invention;

[0028] Figure 8 is a schematic diagram of a top view of a mask in some embodiments of the mask set of the present invention;

[0029] Fig. 9 It is a schematic structural diagram of the splicing result of four masks in some embodiments of the mask set of the present invention. DETAILED DESCRIPTION

[0030] As can be seen from the background technology, in the prior art, different masks in a splicing mask set have strict exposure order restrictions. An incorrect exposure order will cause the positioning marks to fail to splice. Now, the reasons for the exposure order restrictions are analyzed in combination with the positioning marks of a splicing mask set:

[0031] Figure 1 A positioning mark of a stitching mask set is shown.

[0032] like Figure 1 As shown, the positioning mark 11, positioning mark 12, positioning mark 13 and positioning mark 14 in the positioning mark group. Different positioning marks are partially overlapped (i.e. Figure 1 When the positioning mark 11, the positioning mark 12, the positioning mark 13 and the positioning mark 14 are aligned, they are spliced ​​to form a cross-shaped figure in a square frame.

[0033] Since different positioning marks in the positioning mark group are aligned by overlapping the positioning patterns themselves, there are strict restrictions on the formation order of positioning marks during the photolithography process. The positioning marks of the mask used for the subsequent patterning must have overlapping parts with the positioning marks of the mask used for the previous patterning. For example, after patterning with a mask having positioning mark 11, only a mask having positioning mark 12 or a mask having positioning mark 13 can be used for patterning.

[0034] Once the positioning marks are set in different positions or in different exposure orders, the positioning marks may not be stitched together. Figure 2 As shown, it can be seen that there are strict restrictions on the setting position of the positioning mark points on the mask and the exposure order of different masks during the patterning process.

[0035] To solve the technical problem, the present invention provides a positioning mark group. The position of the positioning mark in the positioning mark group can be freely set, which can break through the limitation of the position of the positioning mark on the mask and the limitation of the exposure sequence, can effectively reduce errors, is conducive to the expansion of the process window, and is conducive to reducing the process difficulty.

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0037] refer to Figures 3 to 7 , showing the schematic diagram of the structure of some embodiments of the positioning marker set of the present invention. Among them, Figure 3 is a schematic diagram of the splicing graphics of some embodiments of the positioning mark set of the present invention; Figures 4 to 7 It is a schematic diagram of the structure of each positioning mark of some embodiments of the positioning mark group of the present invention.

[0038] The positioning mark group includes: a first positioning mark 110, the first positioning mark 110 is configured to be set on the first mask, the first positioning mark 110 includes: a first positioning pattern area 111 and a first blank area 112, the first positioning pattern area 111 has a first positioning pattern, and the first blank area 112 has no pattern; a second positioning mark 120, the second positioning mark 120 is configured to be set on the second mask, the second positioning mark 120 includes: a second positioning pattern area 121 and a second blank area 122, the second positioning pattern area 121 has a second positioning pattern, and the second blank area 122 has no pattern; the first positioning mark 110 and the second positioning mark 120 are aligned to achieve the splicing of the pattern of the first mask and the pattern of the second mask; when the first positioning mark 110 and the second positioning mark 120 are aligned, the first positioning pattern and the second positioning pattern are spliced, and the first positioning pattern area 111 is aligned and overlapped with at least a portion of the second blank area 122, and the second positioning pattern area 121 is aligned and overlapped with at least a portion of the first blank area 112.

[0039] The technical solution of the positioning mark group embodiment of the present invention is described in detail below with reference to the accompanying drawings.

[0040] The first positioning mark 110 and the second positioning mark 120 are used for relative alignment to realize the splicing of the pattern of the first mask and the pattern of the second mask; the pattern spliced ​​by the first positioning mark 110 and the second positioning mark 120 is also used for positioning in subsequent processes.

[0041] like Figure 4 As shown, the first positioning mark 110 includes: a first positioning pattern area 111 having a first positioning pattern and a first blank area 112 having no pattern; Figure 5 As shown, the second positioning mark 120 includes: a second positioning pattern area 121 having a second positioning pattern and a second blank area 122 having no pattern.

[0042] It should be noted that Figure 4In the illustrated embodiment, the first positioning pattern area 111 is shown in a red dotted frame, and the first blank area 112 is shown in a blue dotted frame; Figure 5 In the illustrated embodiment, the second positioning pattern area 121 is shown by a red dotted line frame, and the second blank area 122 is shown by a blue dotted line frame.

[0043] When the first positioning mark 110 and the second positioning mark 120 are relatively aligned, the first positioning pattern area 111 is aligned and overlapped with at least a portion of the second blank area 122 , and the second positioning pattern area 121 is aligned and overlapped with at least a portion of the first blank area 112 .

[0044] The alignment and overlap of the positioning pattern and the blank area means that when different positioning marks are aligned, the positioning pattern areas of different positioning marks partially overlap with the range of the blank area, and part of the edge of the positioning pattern area coincides with part of the edge of the blank area.

[0045] Specifically, the first positioning mark 110 and the second positioning mark 120 are aligned with each other, the first positioning pattern and the second positioning pattern are spliced, the first positioning pattern area 111 is aligned and overlapped with part of the second blank area 122, and the second positioning pattern area 121 is aligned and overlapped with part of the first blank area 112.

[0046] The splicing range of the first positioning graphic area 111 and the first blank area 112 is the same shape and size as the splicing range of the second positioning graphic area 121 and the second blank area 122. When the first positioning mark 110 and the second positioning mark 120 are relatively aligned, the range of the first positioning graphic area 111 and the first blank area 112 completely overlaps with the range of the second positioning graphic area 121 and the second blank area 122; in the same plane, the projection of the first positioning graphic area 111 is located within the range of the projection of the second blank area 122, and the partial edge of the projection of the first positioning graphic area 111 coincides with the partial edge of the projection of the second blank area 122; in the same plane, the projection of the second positioning graphic area 121 is located within the range of the projection of the first blank area 112, and the partial edge of the projection of the second positioning graphic area 121 coincides with the partial edge of the projection of the first blank area 112.

[0047] In some embodiments of the present invention, the positioning mark group also includes: a third positioning mark 130, the third positioning mark 130 is configured to be set on a third mask, the third positioning mark 130 includes: a third positioning graphic area 131 and a third blank area 132, the third positioning graphic area 131 has a third positioning graphic, and the third blank area 132 has no graphic.

[0048] The third positioning mark 130 is used to align with the first positioning mark 110 and the second positioning mark 120 to achieve the splicing of the pattern of the first mask, the pattern of the second mask and the pattern of the third mask. Figure 6 As shown, the third positioning mark 130 includes: a third positioning pattern area 131 having a third positioning pattern and a third blank area 132 having no pattern. Figure 6 In the illustrated embodiment, the third positioning pattern area 131 is shown by a red dotted line frame, and the third blank area 132 is shown by a blue dotted line frame.

[0049] When the third positioning mark 130 is aligned with the first positioning mark 110 and the second positioning mark 120, the third positioning pattern area 131 is aligned and overlapped with a part of the first blank area 112 and a part of the second blank area 122. Moreover, the parts where the third positioning pattern area 131 is aligned and overlapped with the first blank area 112 and the second blank area 122 do not overlap.

[0050] The splicing range of the first positioning pattern area 111 and the first blank area 112, the splicing range of the second positioning pattern area 121 and the second blank area 122, and the splicing range of the third positioning pattern area 131 and the third blank area 132 are the same in shape and size. When the first positioning mark 110, the second positioning mark 120, and the third positioning mark 130 are relatively aligned, the range of the first positioning pattern area 111 and the first blank area 112, the range of the second positioning pattern area 121 and the second blank area 122, and the range of the third positioning pattern area 131 and the third blank area 132 completely overlap. In the same plane, the projection of the third positioning graphic area 131 is located within the range of the projection of the first blank area 112, and a portion of the edge of the projection of the third positioning graphic area 131 overlaps with a portion of the edge of the projection of the first blank area 112; in the same plane, the projection of the third positioning graphic area 131 is located within the range of the projection of the second blank area 122, and a portion of the edge of the projection of the third positioning graphic area 131 overlaps with another portion of the edge of the projection of the second blank area 122.

[0051] In some embodiments, the positioning mark group also includes: a fourth positioning mark 140, the fourth positioning mark 140 is configured to be set on a fourth mask, the fourth positioning mark 140 includes: a fourth positioning graphic area 141 and a fourth blank area 142, the fourth positioning graphic area 141 has a fourth positioning graphic, and the fourth blank area 142 has no graphic.

[0052] The fourth positioning mark 140 is used to align with the first positioning mark 110, the second positioning mark 120 and the third positioning mark 130 to achieve the splicing of the first mask pattern, the second mask pattern, the third mask pattern and the fourth mask pattern. Figure 7 As shown, the fourth positioning mark 140 includes: a fourth positioning pattern area 141 having a fourth positioning pattern and a fourth blank area 142 having no pattern. Figure 7 In the illustrated embodiment, the fourth positioning pattern area 141 is shown by a red dotted frame, and the fourth blank area 142 is shown by a blue dotted frame.

[0053] When the fourth positioning mark 140 is aligned with the first positioning mark 110, the second positioning mark 120 and the third positioning mark 130, the fourth positioning pattern area 141 is aligned and overlapped with a part of the first blank area 112, a part of the second blank area 122 and a part of the third positioning pattern area 131. Moreover, the parts where the fourth positioning pattern area 131 is aligned and overlapped with the first blank area 112, the second blank area 122 and the third blank area 132 do not overlap.

[0054] The splicing range of the first positioning pattern area 111 and the first blank area 112, the splicing range of the second positioning pattern area 121 and the second blank area 122, the splicing range of the third positioning pattern area 131 and the third blank area 132, and the splicing range of the fourth positioning pattern area 141 and the fourth blank area 142 are the same in shape and equal in size.

[0055] The first positioning mark 110, the second positioning mark 120, the third positioning mark 130 and the fourth positioning mark 140 are relatively aligned, and the range of the first positioning graphic area 111 and the first blank area 112, the range of the second positioning graphic area 121 and the second blank area 122, the range of the third positioning graphic area 131 and the third blank area 132, and the range of the fourth positioning graphic area 141 and the fourth blank area 142 completely overlap.

[0056] The projection of the fourth positioning graphic area 141 is located within the range of the projection of the first blank area 112, and a partial edge of the projection of the fourth positioning graphic area 141 coincides with a partial edge of the projection of the first blank area 112; in the same plane, the projection of the fourth positioning graphic area 141 is located within the range of the projection of the second blank area 122, and a partial edge of the projection of the fourth positioning graphic area 141 coincides with a partial edge of the projection of the second blank area 122; in the same plane, the projection of the fourth positioning graphic area 141 is located within the range of the projection of the third blank area 132, and a partial edge of the projection of the fourth positioning graphic area 141 coincides with a partial edge of the projection of the third blank area 132.

[0057] like Figures 3 to 7 In some of the embodiments shown, the positioning mark group is used to realize the splicing of 2×2 masks, and the four positioning marks of the positioning mark group are spliced ​​in a 2×2 array, and the positioning graphic area of ​​each positioning mark occupies 1 / 4 of the positioning mark, and the blank area occupies the remaining 3 / 4 of the corresponding positioning mark.

[0058] In some embodiments of the present invention, the positioning pattern includes: an internal sub-pattern and a peripheral sub-pattern, the internal sub-pattern is located between the peripheral sub-pattern and the blank area, and the positioning pattern is one of the first positioning pattern and the second positioning pattern.

[0059] The positioning marks are aligned, and the positioning patterns are spliced ​​into a pattern with an outer frame and an inner pattern, wherein the outer frame surrounds the inner pattern. The inner sub-patterns of different positioning patterns are spliced ​​into the inner pattern, and the outer sub-patterns of different positioning patterns are spliced ​​into the outer frame.

[0060] In some embodiments, the positioning mark group further includes: a third positioning pattern and a fourth positioning pattern; the positioning pattern is one of the first positioning pattern, the second positioning pattern, the third positioning pattern and the fourth positioning pattern.

[0061] Specifically, Figures 3 to 7 In some of the embodiments shown, the outer frame of the pattern formed by the positioning pattern is a square frame, and the inner pattern is a cross. The inner sub-patterns of each positioning pattern are all smaller L-shaped, and the outer sub-patterns of each positioning pattern are also larger L-shaped. The vertex directions of the corners of the inner sub-patterns and the vertex directions of the corners of the outer sub-patterns are respectively in the opposite directions of the diagonal lines of the positioning pattern area.

[0062] In some embodiments of the present invention, different positioning marks are relatively punctual, and the corresponding positioning patterns do not overlap. Different positioning marks are aligned through the positioning pattern area and the blank area, avoiding alignment by overlapping the positioning patterns, breaking through the restrictions on the formation order of the positioning patterns in the alignment process, breaking through the restrictions on the location of the positioning marks on the mask, breaking through the restrictions on the exposure order, effectively reducing errors, and facilitating the expansion of the process window and reducing the process difficulty.

[0063] Specifically, Figure 3 As shown, the first positioning mark 110, the second positioning mark 120, the third positioning mark 130 and the fourth positioning mark 140 are relatively aligned, and the boundaries between the first positioning pattern in the first positioning pattern area of ​​the first positioning mark 110, the second positioning pattern in the second positioning pattern area of ​​the second positioning mark 120, the third positioning pattern in the third positioning pattern area of ​​the third positioning mark 130 and the fourth positioning pattern in the fourth positioning pattern area of ​​the fourth positioning mark 140 coincide with each other, but do not overlap.

[0064] It should be noted that Figure 3 In the illustrated embodiment, the second positioning mark 120 , the third positioning mark 130 , and the fourth positioning mark 140 connected to the first positioning mark 110 are shown by red dotted lines.

[0065] In some embodiments of the present invention, the positioning mark includes: a positioning point, the position of which is used to achieve position alignment between the positioning marks; the positioning mark is one of the first positioning mark 110 and the second positioning mark 120.

[0066] In some embodiments, the positioning mark group further includes: a third positioning pattern and a fourth positioning pattern; the positioning pattern is one of the first positioning pattern, the second positioning pattern, the third positioning pattern and the fourth positioning pattern.

[0067] The positioning points are used to determine the position of the positioning mark and to align the patterns of different masks during splicing.

[0068] In some embodiments, the positioning point is the geometric center of the figure obtained by splicing the first positioning figure and the second positioning figure. Setting the geometric center of the spliced ​​figure as the positioning point can make the distribution of the positioning figures in different positioning marks more uniform, effectively reducing the difficulty of alignment during the splicing process and improving the alignment accuracy.

[0069] It should be noted that Figures 3 to 7 In the illustrated embodiment, the positioning point is shown as a dot with a red fill and a black line.

[0070] Correspondingly, the present invention also provides a mask set.

[0071] refer to Figure 8 and Fig. 9 ,in Figure 8 A schematic diagram of a top view of a mask in some embodiments of the mask set of the present invention is shown; Fig. 9 A schematic structural diagram of the splicing results of four masks in some embodiments of the mask set of the present invention is shown.

[0072] The mask group includes: a first mask 201, wherein the first mask 201 has a first positioning mark group, which is the positioning mark group of the present invention; a second mask 202, wherein the second mask 202 has a second positioning mark group, which is the positioning mark group of the present invention; the distribution positions of the positioning marks in the first positioning mark group correspond to the distribution positions of the positioning marks in the second positioning mark group.

[0073] The distribution positions of the positioning marks in different positioning mark groups correspond to each other, which means that in the positioning mark groups of different masks, the same positioning marks are located at the same position of the masks.

[0074] In some embodiments of the present invention, the mask set further includes: a third mask 203, the third mask 203 having a third positioning mark group, and the third positioning mark group is the positioning mark group of the present invention. The distribution positions of the positioning marks in the first positioning mark group, the distribution positions of the positioning marks in the second positioning mark group, and the distribution positions of the positioning marks in the third positioning mark group correspond to each other.

[0075] In some embodiments, the mask group also includes: a fourth mask 204, the fourth mask 204 having a fourth positioning mark group, and the fourth positioning mark group is the positioning mark group of the present invention; the distribution positions of the positioning marks in the first positioning mark group, the distribution positions of the positioning marks in the second positioning mark group, the distribution positions of the positioning marks in the third positioning mark group, and the distribution positions of the positioning marks in the fourth positioning mark group correspond to each other.

[0076] Specifically, Figure 8 and Fig. 9 In some embodiments shown, the first positioning marks of all positioning mark groups are set at the same position of the mask; the second positioning marks of all positioning mark groups are set at the same position of the mask; the third positioning marks of all positioning mark groups are set at the same position of the mask; and the fourth positioning marks of all positioning mark groups are set at the same position of the mask. However, the positions of different positioning marks on the same mask and in the same positioning mark group are not limited, which breaks through the limitation of the position of the positioning mark on the mask.

[0077] In some embodiments of the present invention, the mask has a splicing area 201a and a non-splicing area 201b; the positioning mark is located in the splicing area 201a, wherein the mask is one of the first mask 201 and the second mask 202, and the positioning mark is the positioning mark corresponding to the mask.

[0078] In some embodiments, the mask set further includes: a third mask and a fourth mask; the mask is one of the first mask, the second mask, the third mask and the fourth mask. Figure 8 and Fig. 9 As shown, the positioning marks of the first positioning mark group are located in the splicing area of ​​the first mask 201; the positioning marks of the second positioning mark group are located in the splicing area of ​​the second mask 202; the positioning marks of the third positioning mark group are located in the splicing area of ​​the third mask 203; and the positioning marks of the fourth positioning mark group are located in the splicing area of ​​the fourth mask 204.

[0079] In some embodiments, the positioning mark is located at the top corner of the mask, wherein the positioning mark is one of the first positioning mark, the second positioning mark, the third positioning mark and the fourth positioning mark, and the mask is a mask corresponding to the positioning mark. Specifically, in the mask group, the first mask, the second mask, the third mask and the fourth mask are spliced ​​in a 2×2 array; in each mask, the splicing area surrounds the non-splicing area. The four positioning marks of each positioning mark group are respectively set at the four top corners of the mask.

[0080] It should be noted that Figure 8 In some of the embodiments shown, the first mask 201 is used as an example for description. In the first mask 201, the non-joined area is shown by a dotted frame, and the annular joint area surrounds the non-joined area.

[0081] It should also be noted that Fig. 9 In some of the embodiments shown, different masks are shown with different filling patterns, wherein the first mask 201 is shown filled with solid red, the second mask 202 and the third mask 203 are shown filled with oblique lines in different directions, and the fourth mask 204 is shown filled with solid white.

[0082] Correspondingly, the present invention further provides a photolithography method, which uses the mask set of the present invention to perform photolithography.

[0083] The photoresist method comprises: providing a substrate having a material layer to be processed; patterning the material layer to be processed using a first mask to form a first pattern layer; and patterning the first pattern layer using a second mask to form a second pattern layer.

[0084] The positions of the positioning marks in the mask set can be set freely, which can break through the restrictions on the positions of the positioning marks on the mask and the exposure sequence, and can effectively reduce errors. The process window of the photolithography method is larger and the process difficulty is lower.

[0085] In some embodiments of the present invention, the step of patterning the first pattern layer using a second mask includes: aligning according to the positions of the positioning points of the positioning marks in the second positioning mark group possessed by the second mask.

[0086] Specifically, in the step of patterning the material layer to be processed using a first mask, the first positioning pattern is transferred to the material layer to be processed to form a first positioning pattern, and the first positioning pattern has a first fixed point.

[0087] In the step of aligning according to the position of the positioning point of the positioning mark in the second positioning mark group possessed by the second mask, the position of the positioning point of the positioning mark in the second positioning mark group possessed by the second mask is determined according to the position of the first fixed point for patterning.

[0088] Specifically, in the step of determining the position of the positioning point of the positioning mark in the second positioning mark group possessed by the second mask according to the position of the first fixed point, the coordinates of the positioning point of the positioning mark in the second positioning mark group possessed by the second mask are set according to the coordinates of the first fixed point. For example, in the step of setting the coordinates of the positioning point of the positioning mark in the second positioning mark group possessed by the second mask, the coordinates of the positioning point of the positioning mark in the second positioning mark group possessed by the second mask can be set to be the same as the coordinates of the first fixed point.

[0089] In summary, each positioning mark includes a positioning pattern area with a positioning pattern and a blank area without a pattern; when different positioning marks are aligned, the positioning patterns of different positioning marks are spliced, and the positioning pattern areas of different positioning marks are at least partially aligned and overlapped with the blank areas; it can be seen that different masks in the mask group of the present invention are spliced ​​based on the positioning patterns and blank areas of the positioning pattern areas, and the positions of the positioning marks in the positioning mark group on the mask are freely set, which can break through the restrictions on the positions of the positioning marks on the mask, can break through the restrictions on the exposure sequence, can effectively reduce errors, and is conducive to the expansion of the process window and the reduction of process difficulty.

[0090] 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 positioning marker set, characterized in that: include: A first positioning mark, wherein the first positioning mark is configured to be set on the first mask, and the first positioning mark includes: a first positioning pattern area and a first blank area, wherein the first positioning pattern area has a first positioning pattern, and the first blank area has no pattern; A second positioning mark, the second positioning mark is configured to be set on the second mask, the second positioning mark includes: a second positioning pattern area and a second blank area, the second positioning pattern area has a second positioning pattern, and the second blank area has no pattern; The first positioning mark and the second positioning mark are aligned to achieve splicing of the pattern of the first mask and the pattern of the second mask; The first positioning mark and the second positioning mark are relatively aligned, the first positioning pattern and the second positioning pattern are spliced, and the first positioning pattern area is aligned and overlapped with at least a portion of the second blank area, and the second positioning pattern area is aligned and overlapped with at least a portion of the first blank area.

2. The positioning mark set according to claim 1, characterized in that: Different positioning marks are relatively punctual, and the corresponding positioning graphics do not overlap.

3. The positioning mark set according to claim 1, characterized in that: The positioning pattern includes: an internal sub-pattern and a peripheral sub-pattern, wherein the internal sub-pattern is located between the peripheral sub-pattern and the blank area, wherein the positioning pattern is one of the first positioning pattern and the second positioning pattern.

4. The positioning mark set according to claim 1, characterized in that: The positioning mark includes: a positioning point, the position of which is used to achieve position alignment between the positioning marks; the positioning mark is one of the first positioning mark and the second positioning mark.

5. The positioning mark set according to claim 4, characterized in that: The positioning point is the geometric center of a figure formed by splicing the first positioning figure and the second positioning figure.

6. The positioning mark set according to claim 1, characterized in that: Also includes: A third positioning mark, the third positioning mark is configured to be set on the third mask, the third positioning mark includes: a third positioning pattern area and a third blank area, the third positioning pattern area has a third positioning pattern, and the third blank area has no pattern; The first positioning mark, the second positioning mark and the third positioning mark are aligned to realize the splicing of the pattern of the first mask, the pattern of the second mask and the pattern of the third mask; The first positioning mark, the second positioning mark and the third positioning mark are relatively aligned, the first positioning pattern, the second positioning pattern and the third positioning pattern are spliced, and the first positioning pattern area and the second positioning pattern area are aligned and overlapped with at least a portion of the third blank area, the second positioning pattern area and the third positioning pattern area are aligned and overlapped with at least a portion of the first blank area, and the third positioning pattern area and the first positioning pattern area are aligned and overlapped with at least a portion of the second blank area.

7. The positioning mark set according to claim 6, characterized in that: Also includes: A fourth positioning mark, the fourth positioning mark is configured to be set on a fourth mask, the fourth positioning mark includes: a fourth positioning pattern area and a fourth blank area, the fourth positioning pattern area has a fourth positioning pattern, and the fourth blank area has no pattern; The first positioning mark, the second positioning mark, the third positioning mark and the fourth positioning mark are aligned to realize the splicing of the pattern of the first mask, the pattern of the second mask, the pattern of the third mask and the pattern of the fourth mask; The first positioning mark, the second positioning mark, the third positioning mark and the fourth positioning mark are relatively aligned, the first positioning pattern, the second positioning pattern, the third positioning pattern and the fourth positioning pattern are spliced, and the first positioning pattern area, the second positioning pattern area and the third positioning pattern area are aligned and overlapped with the fourth blank area; the second positioning pattern area, the third positioning pattern area and the fourth positioning pattern area are aligned and overlapped with the first blank area; the third positioning pattern area, the fourth positioning pattern area and the first positioning pattern area are aligned and overlapped with the second blank area; the fourth positioning pattern area, the first positioning pattern area and the second positioning pattern area are aligned and overlapped with the third blank area.

8. A mask set, characterized in that: A first mask, wherein the first mask has a first positioning mark group, and the first positioning mark group is as described in any one of claims 1 to 5; A second mask, wherein the second mask has a second positioning mark group, and the second positioning mark group is as described in any one of claims 1 to 5; The distribution positions of the positioning marks in the first positioning mark group correspond to the distribution positions of the positioning marks in the second positioning mark group.

9. The mask set according to claim 8, wherein: The mask has a splicing area and a non-splicing area; the positioning mark is located in the splicing area, wherein the mask is one of the first mask and the second mask, and the positioning mark is a positioning mark on the mask.

10. The mask set according to claim 8, wherein: Also includes: a third mask, the third mask having a third positioning mark group, the third positioning mark group as described in claim 6; The distribution positions of the positioning marks in the first positioning mark group, the distribution positions of the positioning marks in the second positioning mark group, and the distribution positions of the positioning marks in the third positioning mark group are consistent with each other.

11. The mask set according to claim 10, wherein: Also includes: A fourth mask, the fourth mask having a fourth positioning mark group, the fourth positioning mark group as described in claim 7; The distribution positions of the positioning marks in the first positioning mark group, the distribution positions of the positioning marks in the second positioning mark group, the distribution positions of the positioning marks in the third positioning mark group, and the distribution positions of the positioning marks in the fourth positioning mark group correspond to each other.

12. The mask set according to claim 11, wherein: The positioning mark is located at a top corner of the mask, wherein the positioning mark is one of the first positioning mark, the second positioning mark, the third positioning mark and the fourth positioning mark, and the mask is a mask corresponding to the positioning mark.

13. A photolithography method, characterized in that: The photolithography method uses the mask set according to any one of claims 8 to 12 to perform photolithography, comprising: Providing a substrate having a material layer to be processed thereon; Using a first mask to pattern the material layer to be processed to form a first pattern layer; The first pattern layer is patterned using a second mask to form a second pattern layer.

14. The photolithography method according to claim 13, wherein: The step of patterning the first pattern layer using a second mask comprises: Alignment is performed according to the positions of the positioning points of the positioning marks in the second positioning mark group possessed by the second mask.

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