CN115586714A - Alignment pattern and measurement method - Google Patents
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- G03F9/00—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically
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- G03F9/7088—Alignment mark detection, e.g. TTR, TTL, off-axis detection, array detector, video detection
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- H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
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Abstract
The present disclosure relates to an alignment pattern and a measurement method, the alignment pattern includes a basic alignment pattern, a first alignment pattern and a second alignment pattern; the basic alignment pattern is positioned in a preset area of the substrate and comprises a plurality of first basic sub-alignment patterns extending along a first direction and a plurality of second basic sub-alignment patterns extending along a second direction; the first alignment pattern is positioned on the epitaxial layer on the substrate and comprises a plurality of strip patterns, and the orthographic projection of the strip patterns in a preset area covers a first basic sub-alignment pattern or a second basic sub-alignment pattern; the second alignment pattern is positioned on the epitaxial layer and comprises a plurality of alignment patterns, and the orthographic projection of the alignment patterns in the preset area surrounds the first basic sub-alignment pattern or the second basic sub-alignment pattern; the embodiment of the disclosure can at least improve the contrast of the alignment pattern and obtain the alignment precision after the epitaxial layer grows, thereby improving the alignment precision of the device and the product yield.
Description
Technical Field
The present disclosure relates to the field of integrated circuit design and manufacturing, and more particularly, to alignment patterns and measurement methods.
Background
In the semiconductor device, epitaxial layers with the same single crystal structure but different doping are formed on a single crystal substrate through an epitaxial technology and are used as a substrate layer or an insulating layer in the vertical direction of the device, so that the breakdown voltage of the device can be improved, and the substrate resistance can be reduced. Before epitaxy, a buried layer is usually formed vertically below a device layer to serve as an insulating layer or a wiring layer, and subsequent device formation is required to be within the projection range of the region, and the lithography level after epitaxy is required to have higher alignment precision, and the alignment precision is required to be higher for devices with smaller sizes.
The overlay accuracy characterizes the degree of positional deviation of the multilayer pattern, and is usually determined by measuring an overlay alignment pattern. However, in the epitaxial layer deposition process, the geometry of each component of the semiconductor device defined by the photolithography process and the etching process may be distorted by the epitaxial growth, and under the condition that the epitaxial layer is grown thickly, the overlay alignment pattern may be expanded, blurred, shifted or even damaged, so that the measurement equipment cannot identify the contour boundary of the overlay alignment pattern, the overlay alignment pattern fails, the overlay accuracy of the device is reduced, and the product yield is reduced.
Disclosure of Invention
Based on the above, the present disclosure provides an alignment pattern and a measurement method, which at least can improve the contrast of the alignment pattern, prevent the boundary of the alignment pattern profile from being unidentified due to epitaxial layer growth, and obtain the overlay accuracy after epitaxial layer growth, thereby improving the overlay accuracy and the product yield of the device.
To solve the above technical problem and other problems, according to some embodiments, an aspect of the present disclosure provides an alignment pattern including a base alignment pattern, a first alignment pattern, and a second alignment pattern; the basic alignment pattern is positioned in a preset area of the substrate and comprises a plurality of first basic sub-alignment patterns extending along a first direction and a plurality of second basic sub-alignment patterns extending along a second direction; the first alignment pattern is positioned on the epitaxial layer on the substrate and comprises a plurality of strip patterns, and the orthographic projection of the strip patterns in a preset area covers a first basic sub-alignment pattern or a second basic sub-alignment pattern; the second alignment pattern is positioned on the epitaxial layer and comprises a plurality of alignment patterns, and the orthographic projection of the alignment patterns in the preset area surrounds the first basic sub-alignment pattern or the second basic sub-alignment pattern; the second alignment pattern is in orthographic projection of the epitaxial layer, far away from the substrate surface, in the preset region, and surrounds the first alignment pattern, and in orthographic projection of the epitaxial layer, far away from the substrate surface, in the preset region; the first direction intersects the second direction.
In the alignment patterns of the above embodiment, a basic alignment pattern, a first alignment pattern, and a second alignment pattern are sequentially disposed on a substrate, and the basic alignment pattern includes a plurality of first basic sub-alignment patterns and a plurality of second basic sub-alignment patterns; the first alignment pattern comprises a plurality of strip patterns, and the orthographic projection of the strip patterns in the preset area covers a first basic sub-alignment pattern or a second basic sub-alignment pattern; the second alignment pattern comprises a plurality of alignment patterns, and the orthographic projection of the alignment patterns in the preset area surrounds a first basic sub-alignment pattern or a second basic sub-alignment pattern; the orthographic projection of the second alignment pattern in the preset area surrounds the orthographic projection of the first alignment pattern in the preset area, so that the problem that the outline boundary of the alignment pattern cannot be identified due to expansion, blurring and deviation of the alignment pattern and even damage of the alignment pattern caused by epitaxial layer growth is avoided, and the alignment precision and the product yield of the device are improved.
In some embodiments, the first direction is perpendicular to the second direction; the strip pattern is rectangular.
In some embodiments, the alignment pattern includes a plurality of first sub-alignment patterns extending in a first direction and a plurality of second sub-alignment patterns extending in a second direction; the first sub-alignment patterns are distributed on two opposite sides of a first basic sub-alignment pattern along the second direction, or distributed on two opposite sides of a second basic sub-alignment pattern along the second direction; the second sub-alignment patterns are distributed on two opposite sides of a second basic sub-alignment pattern along the first direction, or on two opposite sides of a second basic sub-alignment pattern along the first direction.
In some embodiments, the first sub-alignment patterns are distributed on two opposite sides of a long bar pattern along the second direction; the second sub-alignment patterns are distributed on two opposite sides of the long strip pattern along the first direction; a first preset interval is reserved between the first sub-alignment pattern and the long strip patterns adjacent to the first sub-alignment pattern along the second direction; a second preset interval is reserved between the second sub-alignment pattern and the long strip patterns adjacent to the second sub-alignment pattern along the first direction.
In some embodiments, the first sub-alignment pattern and the second sub-alignment pattern are both trench-shaped; a third preset interval is formed between the second sub-alignment patterns adjacent to each other along the first direction; and a fourth preset interval is formed between the first sub-alignment patterns adjacent to each other along the second direction.
In some embodiments, the epitaxial layer comprises a photoresist layer, the photoresist layer being located on the substrate; the strip pattern is an opening pattern or an etching pattern, and the opening pattern is positioned on the photoresist layer.
In some embodiments, the epitaxial layer includes a first semiconductor layer and a second semiconductor layer, the first alignment pattern is on the first semiconductor layer, and the second alignment pattern is on the second semiconductor layer; between the first semiconductor layer substrate and the second semiconductor layer; or the second semiconductor layer is located between the substrate and the first semiconductor layer.
In some embodiments, the alignment pattern includes at least one of the following features: the length of the first basic sub-alignment pattern or the second basic sub-alignment pattern is 28 μm-32 μm; the width of the first basic sub-alignment pattern or the second basic sub-alignment pattern is 1.5 μm-2.5 μm; the pitch of the first basic sub-alignment patterns adjacent to each other in the second direction is 16 μm to 20 μm; the pitch of the second basic sub-alignment patterns adjacent to each other in the first direction is 16 μm to 20m; the second sub-alignment pattern has a pitch of 12.2 μm to 13.8 μm from the first sub-alignment pattern adjacent thereto in the first direction; the length of the strip pattern is 28-39 μm; the width of the stripe pattern is 4.4 μm to 7.2. Mu.m.
In some embodiments, the first predetermined pitch is 2.3 μm to 3.5 μm; the second preset interval is 13.3-14.5 μm; the third preset interval is 0.26-0.30 μm; the fourth predetermined pitch is 0.38 μm to 0.42 μm.
According to some embodiments, a further aspect of the present disclosure provides a measurement method implemented based on the alignment pattern of any one of the above embodiments; the measuring method comprises the following steps: acquiring a first initial offset of the central point of the first alignment graph compared with the central point of the basic alignment graph, and calculating a first target offset according to the first initial offset and a first preset rule, wherein the first target offset is an actual offset of a layer where the first alignment graph is located relative to a layer where the basic alignment graph is located; and acquiring a second initial offset of the central point of the second alignment graph compared with the central point of the basic alignment graph, and calculating a second target offset according to the second initial offset and a second preset rule, wherein the second target offset is the actual offset of the layer where the second alignment graph is located relative to the layer where the basic alignment graph is located.
In the measuring method of the embodiment, the actual offset is obtained by obtaining the first initial offset, the first target offset is calculated, the second initial offset is obtained, and the second target offset is calculated to obtain the actual offset, so that the online overlay error measurement result is verified, the accuracy of the online measurement result is judged, the online measurement result is monitored, the online overlay process and the subsequent process are subjected to auxiliary guidance according to the actual offset measurement result, and the overlay accuracy and the product yield of the device are improved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1A is a schematic top view of an embodiment of the present disclosure before epitaxial growth of an alignment mark;
FIG. 1B is a schematic top view of an embodiment of the present disclosure after epitaxial growth of an alignment mark;
FIG. 2 is a schematic top view of an alignment pattern according to an embodiment of the present disclosure;
FIG. 3 is a schematic top view of an alignment pattern according to another embodiment of the present disclosure;
FIG. 4 is a schematic top view of an alignment pattern according to another embodiment of the present disclosure;
FIG. 5 is a schematic top view of an alignment pattern according to still another embodiment of the present disclosure;
fig. 6 is a schematic flow chart of a measurement method according to an embodiment of the disclosure.
Description of reference numerals:
10. a substrate; 11. an epitaxial layer; 101. a first alignment area; 102. a second alignment area; 100. a base alignment pattern; 110. a first base sub-alignment pattern; 120. a second base sub-alignment pattern; 200. a first alignment pattern; 210. a strip pattern; 300. a second alignment pattern; 310. aligning the pattern; 311. a first sub-alignment pattern; 312. a second sub-alignment pattern.
Detailed Description
To facilitate an understanding of the present disclosure, the present disclosure will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present disclosure are shown in the drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein in the description of the disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure.
It will be understood that when an element or layer is referred to as being "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it can be directly on, adjacent to, connected or coupled to the other elements or layers or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly adjacent to," "directly connected to" or "directly coupled to" other elements or layers, there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, doping types and/or sections, these elements, components, regions, layers, doping types and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, doping type or section from another element, component, region, layer, doping type or section. Thus, a first element, component, region, layer, doping type or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present disclosure.
Spatial relational terms, such as "under," "below," "under," "over," and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements or features described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary terms "under" and "under" can encompass both an orientation of above and below. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations) and the spatial descriptors used herein interpreted accordingly.
As used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Also, as used herein, the term "and/or" includes any and all combinations of the associated listed items.
It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present disclosure, and although the drawings only show the components related to the present disclosure and are not drawn according to the number, shape and size of the components in actual implementation, the type, quantity and proportion of each component in actual implementation may be changed arbitrarily, and the component layout may be more complicated.
Referring to fig. 1A to 1B, a conventional alignment pattern is formed by a pattern represented by lA before epitaxial growth as an overlay alignment pattern for photolithography overlay measurement, thereby performing a subsequent process according to the overlay alignment pattern; however, for the process with a large epitaxial layer thickness or a severe pattern distortion, referring to fig. 1B, due to the limitation of the epitaxial process, the film coverage of the epitaxial layer growth is good, the epitaxial growth distorts the geometric shapes of each component of the semiconductor device defined by the photolithography process and the etching process, resulting in the smoothing of the vertical end surface of the overlay alignment pattern, and the step depth of the overlay alignment pattern after the epitaxial growth is insufficient, and in addition, the shape of the overlay alignment pattern after the growth may change constantly with the epitaxial process and the end surface shape, resulting in the expansion, blurring, shifting or even damage of the overlay alignment pattern, resulting in the contrast reduction or even failure of the overlay alignment pattern, so that the measuring equipment cannot accurately identify the contour boundary of the overlay alignment pattern, reducing the overlay accuracy of the device, and further reducing the product yield.
Referring to fig. 2 to 5, according to some embodiments, the present disclosure provides an alignment pattern including a basic alignment pattern 100, a first alignment pattern 200, and a second alignment pattern 300; the basic alignment pattern 100 is located in a predetermined region of the substrate 10, the predetermined region includes a first alignment region 101 and a second alignment region 102 adjacent to each other along a first direction, the first alignment region 101 and the second alignment region 102 include rectangles in shape, the basic alignment pattern 100 includes a plurality of first basic sub-alignment patterns 110 extending along the first direction and a plurality of second basic sub-alignment patterns 120 extending along a second direction, the first basic sub-alignment patterns 110 are located in the first alignment region 101, and the first basic sub-alignment patterns 110 are located in the first alignment region 101; the first alignment pattern 200 is located on the epitaxial layer 11 on the substrate 10 and includes a plurality of bar patterns 210, and an orthogonal projection of the bar patterns 210 in a predetermined area covers a first basic sub-alignment pattern 110 or a second basic sub-alignment pattern 120; the second alignment pattern 300 is located on the epitaxial layer 11 and includes a plurality of alignment patterns 310, wherein an orthogonal projection of the alignment patterns 310 in a predetermined area surrounds the first basic sub-alignment pattern 110 or the second basic sub-alignment pattern 120; wherein, the orthographic projection of the second alignment pattern 300 in the preset area surrounds the orthographic projection of the first alignment pattern 200 in the preset area; the first direction intersects the second direction, e.g., the first direction is the OX direction and the second direction is the OY direction; the substrate 10 may be formed using a semiconductor material, an insulating material, a conductive material, or any combination thereof. The substrate 10 may have a single-layer structure or a multi-layer structure. For example, the substrate 10 may be a substrate such as a silicon (Si) substrate 10, a silicon germanium (SiGe) substrate 10, a silicon germanium carbon (SiGeC) substrate 10, a silicon carbide (SiC) substrate 10, a gallium arsenide (GaAs) substrate 10, an indium arsenide (InAs) substrate 10, an indium phosphide (InP) substrate 10, or other III/V semiconductor substrate 10 or II/VI semiconductor substrate 10. Alternatively, and for example, the substrate 10 may be a layered substrate 10 comprising a material such as Si/SiGe, si/SiC, silicon-on-insulator (SOI), or silicon germanium-on-insulator.
With reference to fig. 2 to 5, in the alignment patterns of the above embodiment, the basic alignment pattern 100, the first alignment pattern 200 and the second alignment pattern 300 are sequentially disposed on the substrate 10, and the basic alignment pattern 100 includes a plurality of first basic sub-alignment patterns 110 and a plurality of second basic sub-alignment patterns 120; the first alignment pattern 200 includes a plurality of bar patterns 210, and the orthographic projection of the bar patterns 210 on the predetermined area covers a first basic sub-alignment pattern 110 or a second basic sub-alignment pattern 120; the second alignment pattern 300 includes a plurality of alignment patterns 310, and an orthogonal projection of the alignment patterns 310 in a predetermined area surrounds the first basic sub-alignment pattern 110 or the second basic sub-alignment pattern 120; the orthographic projection of the second alignment pattern 300 in the preset area surrounds the orthographic projection of the first alignment pattern 200 in the preset area, so that the problem that the outline boundary of the alignment pattern cannot be identified due to expansion, blurring, deviation and even damage of the alignment pattern caused by growth of the epitaxial layer 11 is avoided, and the alignment precision and the product yield of the device are improved.
Referring to fig. 4, in some embodiments, the first direction, e.g., the OX direction, is perpendicular to the second direction, e.g., the OY direction; the stripe patterns 210 are rectangular, so that the stripe patterns 210 surround the first and second basic sub-alignment patterns 110 and 120 more uniformly.
Referring to fig. 3, in some embodiments, the alignment pattern 310 includes a plurality of first sub-alignment patterns 311 extending along a first direction and a plurality of second sub-alignment patterns 312 extending along a second direction; the first sub-alignment patterns 311 are disposed on opposite sides of a first base sub-alignment pattern 110 in the second direction or on opposite sides of a second base sub-alignment pattern 120 in the second direction; the second sub-alignment patterns 312 are distributed on opposite sides of a second base sub-alignment pattern 120 in a first direction, e.g., an OX direction, or on opposite sides of a second base sub-alignment pattern 120 in the first direction, e.g., an OY direction; through the position relationship arrangement of the first sub-alignment pattern 311 and the first basic sub-alignment pattern 110 and the second sub-alignment pattern 312 and the second basic sub-alignment pattern 120, the comparison of alignment patterns before and after the growth of the epitaxial layer 11 is realized, and the auxiliary guidance is performed on the epitaxial process and the subsequent process, thereby improving the alignment precision.
Referring to fig. 5, in some embodiments, the first sub-alignment patterns 311 are distributed on two opposite sides of the bar pattern 210 along the second direction; the second sub-alignment patterns 312 are distributed on two opposite sides of one bar pattern 210 along the first direction; the first sub-alignment pattern 311 has a first preset distance between the orthographic projection of the preset region and the adjacent long bar pattern 210 along the second direction; the second sub-alignment pattern 312 has a second predetermined distance between the orthogonal projection of the predetermined region and the bar pattern 210 adjacent to the second sub-alignment pattern along the first direction, such as the OX direction, and the second direction, such as the OY direction, wherein the first and second predetermined distances can be observed through an Optical Microscope (OM), so that the offset between the first and second sub-alignment patterns 311 and 312 and the bar pattern 210 can be directly obtained.
With continued reference to fig. 5, in some embodiments, the first sub-alignment pattern 311 and the second sub-alignment pattern 312 are both trench-shaped; a third preset interval is provided between the second sub-alignment patterns 312 adjacent in the first direction; a fourth preset interval is provided between the first sub-alignment patterns 311 adjacent in the second direction; the trench-shaped first sub-alignment pattern 311 and the second sub-alignment pattern 312 may be formed by a dry etching process or a wet etching process, for example, a plasma etching process may be used, where the plasma etching process is to activate a reaction gas into active particles by using a high-frequency glow discharge reaction, and the active particles are diffused to an etched portion to react with an etched material to form a volatile product to be removed, so as to increase a rate of the process. Since the first sub-alignment pattern 311 and the second sub-alignment pattern 312 are both in the groove shape, the third predetermined pitch and the fourth predetermined pitch can be observed by a Scanning Electron Microscope (CDSEM) for measuring a feature size, and the accuracy of the measurement accuracy and the measured pitch can be improved due to the high resolution image display capability of the CDSEM.
Referring to fig. 4, in some embodiments, epitaxial layer 11 includes a photoresist layer on the substrate; the stripe pattern 210 is an opening pattern or an etching pattern, and the opening pattern is on the photoresist layer. The photoresist is a photoresist etching film material with solubility changed by irradiation or radiation of ultraviolet light, electron beam, ion beam, X-ray, etc., and the material of the photoresist layer can include ultraviolet photoresist, deep ultraviolet photoresist, X-ray photoresist, electron beam photoresist, ion beam photoresist, etc.; for example, the ultraviolet photoresist can comprise cinnamate photoresist, the cinnamate photoresist can comprise polyvinyl alcohol cinnamate photoresist, polyethylene oxyethyl cinnamate photoresist, cinnamylidene diester photoresist and the like, the cinnamate photoresist belongs to linear high polymer, is hardly influenced by oxygen under exposure, does not need nitrogen protection, has the resolution of 1 mu m, can be maintained for 0.5h under a film layer at 190 ℃ after development, and has clear and neat lines of a graph formed by the cinnamate photoresist, high sensitivity and resolution, strong corrosion resistance and good adhesiveness and heat resistance.
Referring to fig. 3 to 4, in some embodiments, the epitaxial layer 11 includes a first semiconductor layer (not shown) and a second semiconductor layer (not shown), the first alignment pattern 200 is located on the first semiconductor layer, and the second alignment pattern 300 is located on the second semiconductor layer; the first semiconductor layer is positioned between the substrate and the second semiconductor layer; or the second semiconductor layer is located between the substrate and the first semiconductor layer, so that the first alignment pattern 200 and the second alignment pattern 300 are more flexibly arranged, thereby adapting to different application scenarios.
Referring to fig. 5, in some embodiments, the length of the first base sub-alignment pattern 110 or the second base sub-alignment pattern 120 may be set to be in a range of 28 μm to 32 μm, for example, 28 μm, 29 μm, 30 μm, 31 μm, or 32 μm.
Referring to fig. 5, in some embodiments, the width of the first basic sub-alignment pattern 110 or the second basic sub-alignment pattern 120 may be set to be in a range of 1.5 μm to 2.5 μm, for example, may be set to be 1.5 μm, 2 μm, or 2.5 μm.
With continued reference to fig. 5, in some embodiments, the pitch of the first basic sub-alignment patterns 110 adjacent to each other along the second direction, e.g., the OY direction, may be set to be in a range of 16 μm to 20 μm, e.g., 16 μm, 17 μm, 18 μm, 19 μm, or 20 μm.
With continued reference to FIG. 5, in some embodiments, the pitch of the second basic sub-alignment patterns 120 adjacent to each other along the first direction, e.g., the OX direction, may be set to be in a range of 16 μm-20 μm, e.g., 16 μm, 17 μm, 18 μm, 19 μm, or 20 μm.
With continued reference to fig. 5, in some embodiments, the distance between the orthogonal projection of the first sub-alignment pattern 311 on the predetermined area and the orthogonal projection of the adjacent stripe pattern 210 on the predetermined area along the second direction, for example, the OY direction, may be set to be 1.2 μm to 2.8 μm, for example, may be set to be 1.2 μm, 1.4 μm, 1.7 μm, 2 μm, 2.3 μm, 2.6 μm, or 2.8 μm.
With continued reference to fig. 5, in some embodiments, the pitch between the second sub-alignment pattern 312 and the first sub-alignment pattern 311 adjacent thereto along the first direction, e.g., the OX direction, may be set to be in a range of 12.2 μm to 13.8 μm, e.g., may be set to be 12.2 μm, 12.4 μm, 13 μm, 13.3 μm, 13.6 μm or 13.8 μm, etc.
With continued reference to FIG. 5, in some embodiments, the length of the stripe pattern 210 may be set to be in a range of 28 μm-39 μm, such as 28 μm, 34.6 μm, 35.2 μm, 35.8 μm, 36.4 μm, 37 μm, or 39 μm.
With continued reference to FIG. 5, in some embodiments, the width of the stripe pattern 210 may be set to be in a range of 4.4 μm to 7.2 μm, for example, 4.4 μm, 4.6 μm, 5.2 μm, 5.8 μm, 6.4 μm, 7 μm, or 7.2 μm.
Referring to fig. 5, in some embodiments, the lengths of the first sub-alignment pattern 311 and the second sub-alignment pattern 312 may be set to be in a range of 9.8 μm to 10.2 μm, for example, 9.8 μm, 9.9 μm, 10 μm, 10.1 μm, or 10.2 μm.
With continued reference to fig. 5, in some embodiments, the shapes of the first alignment region 101 and the second alignment region 102 include squares, the side lengths of the first alignment region 101 and the second alignment region 102 may be set to range from 39 μm to 44 μm, for example, the side lengths of the first alignment region 101 and the second alignment region 102 may be set to 39 μm, 40 μm, 41 μm, 42 μm, 43 μm or 44 μm, etc.; thereby realizing alignment patterns with different sizes to adapt to devices with different sizes.
With continued reference to fig. 5, in some embodiments, the first predetermined pitch may be set to range from 2.3 μm to 3.5 μm, for example, the first predetermined pitch may be set to be 2.3 μm, 2.6 μm, 2.9 μm, 3.2 μm or 3.5 μm; the second preset pitch may be set in a range of 13.3 μm to 14.5 μm, for example, the second preset pitch may be set to 13.3 μm, 13.6 μm, 13.9 μm, 14.2 μm, 14.5 μm, or the like; the third preset pitch may be set in a range of 0.26 μm to 0.3 μm, for example, the third preset pitch may be set in a range of 0.26 μm, 0.27 μm, 0.28 μm, 0.29 μm, 0.3 μm, or the like; the fourth preset pitch may be set in a range of 0.38 μm to 0.42 μm, for example, the fourth preset pitch may be set to 0.38 μm, 0.39 μm, 0.4 μm, 0.41 μm, or 0.42 μm, etc.; thereby realizing alignment patterns with different sizes to adapt to devices with different sizes.
Referring to fig. 5 to 6, according to some embodiments, the present disclosure provides a measurement method implemented based on an alignment pattern in any one of the above embodiments, the measurement method including:
step S10: acquiring a first initial offset of the center point of the first alignment pattern 200 compared with the center point of the basic alignment pattern 100, and calculating a first target offset according to the first initial offset and a first preset rule, wherein the first target offset is an actual offset of a layer where the first alignment pattern 200 is located relative to a layer where the basic alignment pattern 100 is located;
step S20: a second initial offset of the center point of the second alignment pattern 300 compared to the center point of the base alignment pattern 100 is obtained, and a second target offset is calculated according to the second initial offset and a second preset rule, wherein the second target offset is an actual offset of the layer where the second alignment pattern 300 is located relative to the layer where the base alignment pattern 100 is located.
With continued reference to fig. 5 to 6, in step S10, a first initial offset of the center point of the first alignment pattern 200 from the center point of the base alignment pattern 100 may be obtained through an Optical Microscope (OM). With continued reference to fig. 5 to 6, in step S20, a second initial offset of the center point of the second alignment pattern 300 compared to the center point of the basic alignment pattern 100 may be obtained through a Scanning Electron Microscope (CDSEM) for feature size measurement, which may improve the measurement accuracy and the accuracy of the measured offset due to the high resolution image display capability of the CDSEM.
In the measuring method of the embodiment, the actual offset is obtained by obtaining the first initial offset, the first target offset is calculated, the second initial offset is obtained, and the second target offset is calculated to obtain the actual offset, so that the online overlay error measurement result is verified, the accuracy of the online measurement result is judged, the online measurement result is monitored, the online overlay process and the subsequent process are subjected to auxiliary guidance according to the actual offset measurement result, and the overlay accuracy and the product yield of the device are improved.
Note that the above embodiments are for illustrative purposes only and are not meant to limit the present disclosure.
The embodiments in the present specification are all described in a progressive manner, and each embodiment focuses on differences from other embodiments, and portions that are the same and similar between the embodiments may be referred to each other.
All possible combinations of the technical features in the above embodiments may not be described for the sake of brevity, but should be considered as being within the scope of the present disclosure as long as there is no contradiction between the combinations of the technical features.
The above examples merely represent several embodiments of the present disclosure, which are described in more detail and detail, but are not to be construed as limiting the scope of the disclosure. It should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the concept of the present disclosure, and these changes and modifications are all within the scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the appended claims.
Claims (10)
1. An alignment pattern, comprising:
the basic alignment graph is positioned in a preset area of the substrate and comprises a plurality of first basic sub-alignment graphs extending along a first direction and a plurality of second basic sub-alignment graphs extending along a second direction;
the first alignment pattern is positioned on the epitaxial layer on the substrate and comprises a plurality of strip patterns, and the orthographic projection of the strip patterns in the preset area covers one first basic sub-alignment pattern or one second basic sub-alignment pattern;
the second alignment pattern is positioned on the epitaxial layer and comprises a plurality of alignment patterns, and the orthographic projection of the alignment patterns in the preset area surrounds the first basic sub-alignment pattern or the second basic sub-alignment pattern;
wherein, the orthographic projection of the second alignment graph in the preset area surrounds the orthographic projection of the first alignment graph in the preset area; the first direction intersects the second direction.
2. The alignment pattern of claim 1, wherein the first direction is perpendicular to the second direction;
the strip pattern is rectangular.
3. The alignment pattern of claim 2, wherein the alignment pattern comprises a plurality of first sub-alignment patterns extending along the first direction and a plurality of second sub-alignment patterns extending along the second direction;
the first sub-alignment patterns are distributed on two opposite sides of the first basic sub-alignment pattern along the second direction, or distributed on two opposite sides of the second basic sub-alignment pattern along the second direction;
the second sub-alignment patterns are distributed on two opposite sides of a second basic sub-alignment pattern along the first direction, or on two opposite sides of a second basic sub-alignment pattern along the first direction.
4. The alignment pattern of claim 3, wherein:
the first sub-alignment patterns are distributed on two opposite sides of the long strip pattern along the second direction;
the second sub-alignment patterns are distributed on two opposite sides of the long strip pattern along the first direction;
the orthographic projection of the first sub-alignment pattern in the preset area has a first preset distance between the orthographic projections of the long strip patterns adjacent to the first sub-alignment pattern in the second direction in the preset area;
the second sub-alignment pattern has a second preset distance from the long bar pattern adjacent to the second sub-alignment pattern along the first direction.
5. The alignment pattern of claim 4, wherein the first sub-alignment pattern and the second sub-alignment pattern are both trench-shaped;
a third preset interval is formed between the second sub-alignment patterns adjacent to each other along the first direction;
and a fourth preset interval is formed between the first sub-alignment patterns adjacent to each other along the second direction.
6. The alignment pattern of claim 1, wherein the epitaxial layer comprises a photoresist layer, the photoresist layer being on the substrate;
the strip patterns are opening patterns or etching patterns, and the opening patterns are positioned on the photoresist layer.
7. The alignment pattern of claim 1, wherein the epitaxial layer comprises a first semiconductor layer and a second semiconductor layer;
the first alignment pattern is located on the first semiconductor layer, and the second alignment pattern is located on the second semiconductor layer;
the first semiconductor layer is located between the substrate and the second semiconductor layer; or
The second semiconductor layer is located between the substrate and the first semiconductor layer.
8. The alignment pattern of claim 3, comprising at least one of the following features:
the length of the first basic sub-alignment pattern or the second basic sub-alignment pattern is 28 μm to 32 μm;
the width of the first basic sub-alignment pattern or the second basic sub-alignment pattern is 1.5 μm-2.5 μm;
the pitch of the first basic sub-alignment patterns adjacent to each other along the second direction is 16-20 μm;
the pitch of the second basic sub-alignment patterns adjacent to each other along the first direction is 16-20 μm;
the second sub-alignment pattern has a pitch of 12.2 μm to 13.8 μm from the first sub-alignment pattern adjacent thereto in the first direction;
the length of the strip pattern is 28-39 μm;
the width of the strip pattern is 4.4-7.2 μm.
9. The alignment pattern of claim 5, wherein:
the first preset interval is 2.3-3.5 mu m;
the second preset interval is 13.3-14.5 mu m;
the third preset distance is 0.26-0.30 mu m;
the fourth preset interval is 0.38-0.42 μm.
10. A measurement method, characterized by being implemented based on the alignment pattern of any one of claims 1 to 9; the measuring method comprises the following steps:
acquiring a first initial offset of the center point of the first alignment graph compared with the center point of the basic alignment graph, and calculating a first target offset according to the first initial offset and a first preset rule, wherein the first target offset is an actual offset of a layer where the first alignment graph is located relative to a layer where the basic alignment graph is located;
and obtaining a second initial offset of the center point of the second alignment graph compared with the center point of the basic alignment graph, and calculating a second target offset according to the second initial offset and a second preset rule, wherein the second target offset is an actual offset of a layer where the second alignment graph is located relative to a layer where the basic alignment graph is located.
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