CN107703715B - Method for repairing mask pattern defects - Google Patents
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- CN107703715B CN107703715B CN201610642440.6A CN201610642440A CN107703715B CN 107703715 B CN107703715 B CN 107703715B CN 201610642440 A CN201610642440 A CN 201610642440A CN 107703715 B CN107703715 B CN 107703715B
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- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
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- G03F1/72—Repair or correction of mask defects
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Abstract
The invention provides a method for repairing mask pattern defects, and relates to the technical field of semiconductors. The repairing method of the invention reduces the pixels of the mask defect graph or the normal mask graph to correspondingly reduce the size of the mask defect graph or the normal mask graph, enlarges different areas between the mask defect graph and the normal mask graph, wherein the different areas are defect areas, and further easily identifies and positions the position of the defect area.
Description
Technical Field
The invention relates to the technical field of semiconductors, in particular to a method for repairing defects of a mask pattern.
Background
Semiconductor Integrated Circuits (ICs), i.e., semiconductor chips, are subjected to a plurality of processes such as material preparation, plate making, photolithography, cleaning, etching, impurity doping, and chemical mechanical polishing during the manufacturing process, wherein the photolithography process is the most critical process. The progress of semiconductor chip manufacturing process is determined by photolithography, and it is due to the great progress of photolithography that the integrated circuit manufacturing process is brought from the micron period to the deep submicron period, and further to the nanometer period. The photolithography process requires a complete set (several or up to ten) of photolithographic masking stencils, referred to as photolithographic masks (masks), having a specific geometry, that are precisely registered with each other. Photolithographic masks are essentially "negatives" of photoresist (also known as photoresist) layers in a photolithographic process onto which the geometric patterns of an original integrated circuit design layout are printed. That is, from the original design layout of the integrated circuit to the formation of the circuit pattern on the wafer, a plate making process is needed, i.e., a set of lithography masks on which the design pattern of the original design layout of the integrated circuit is printed is needed to be made as the "negative film". The photoetching process is to transfer the geometric figure on the 'photographic negative film' onto the wafer to form the circuit figure on the wafer.
Dozens or even dozens of photoetching procedures are often needed in the chip manufacturing process, each photoetching procedure needs to use one photoetching mask plate, and the quality of each photoetching mask plate directly influences the quality of photoetching patterns on a wafer, so that the yield of chips is influenced. Therefore, the mask pattern on the photolithographic reticle must be intact to present the complete pattern of the original integrated circuit design layout. Once the incomplete mask pattern is transferred to the wafer, the quality of the finished wafer product is not good.
Therefore, the repair of the mask pattern defect is required to be performed after the photolithography mask is manufactured, the repair of the mask pattern defect is a key step for manufacturing a high-quality mask, the repair method of the mask pattern defect at present usually defines a repair area to be filled (for example, deposited) or removed (for example, etched) manually, first obtains an image of a mask pattern corresponding to a mask pattern defect position and an image of a normal mask pattern corresponding to a normal mask pattern position, wherein the image of the mask pattern corresponding to the mask pattern defect position is a mask image to be repaired, the image of the normal mask pattern corresponding to the normal mask pattern position is a normal mask image, obtains edge profiles of the mask image to be repaired and the normal mask image through a pattern processing device, and performs an overlap (overlap) comparison, if the edge profile of the mask image to be repaired has a protrusion compared with the edge profile of the normal mask image, the protrusion is a defect region (also called a region to be repaired), and the corresponding etching repair is performed on the defects of the photomask, whereas if the edge profile of the mask image to be repaired has a depression compared to that of the normal mask image, the protruding part is a defect area, the defect area of the photolithography mask is correspondingly deposited and repaired, with the rapid development of the large-scale integrated circuit process technology, the minimum critical dimension of the mask is reduced to 28nm node and below, the nanometer micro defect on the mask is difficult to be ignored, but because there is not enough difference between the defective pattern and the normal pattern, the conventional pattern overlay method cannot accurately locate the position of the defective region and the repair is failed, causing the quality of the reticle to degrade and potentially severely adversely affecting the wafer printing process.
Therefore, in view of the above problems, it is necessary to provide a new method for repairing the mask pattern defect.
Disclosure of Invention
In this summary, concepts in a simplified form are introduced that are further described in the detailed description. This summary of the invention is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
In view of the defects in the prior art, an embodiment of the present invention provides a method for repairing a mask pattern defect, including:
acquiring an SEM image of a mask pattern corresponding to a mask pattern defect position on a photoetching mask plate and an SEM image of a normal mask pattern corresponding to the mask pattern defect position, wherein the SEM image of the mask pattern corresponding to the mask pattern defect position is the mask defect image, and the SEM image of the normal mask pattern corresponding to the normal mask pattern position is the normal mask image;
extracting edge features of the mask defect image and the normal mask image, converting the edge features into a geometric figure format, and storing the geometric figure format to obtain an initial mask defect figure and an initial normal mask figure;
filling blank areas in the edge profiles of the initial mask defect pattern and the initial normal mask pattern to form a mask defect pattern and a normal mask pattern;
reducing the pixels of the mask defect graph or the normal mask graph to correspondingly reduce the size of the mask defect graph or the normal mask graph, so as to respectively obtain a middle mask defect graph or a middle normal mask graph;
extracting edge features of the intermediate mask defect graph or the intermediate normal mask graph, converting the edge features into a geometric graph format, and storing the geometric graph format so as to obtain an edge outline graph of the intermediate mask defect graph or an edge outline graph of the intermediate normal mask graph;
performing overlapping comparison on the edge outline graph of the intermediate mask defect graph and the initial normal mask graph, or performing overlapping comparison on the edge outline graph of the intermediate normal mask graph and the initial mask defect graph, and identifying an un-overlapped area, wherein the un-overlapped area is a defect area, so as to position the position of a defect in the photoetching mask plate;
and repairing the defects on the photoetching mask.
Further, before the step of reducing the pixels of the mask defect pattern or the normal mask pattern, the method further comprises the following steps: and detecting the photoetching mask plate to preliminarily judge whether the defects of the mask pattern on the photoetching mask plate are filled and repaired or removed and repaired.
Further, the method for detecting the photoetching mask plate comprises the following steps:
and performing overlapping comparison on the mask defect image and the normal mask image, if the mask defect image comprises a bulge defect compared with the normal mask image, removing and repairing the bulge defect by using the removing and repairing method, and if the mask defect image comprises a recess defect compared with the normal mask image, repairing the recess defect by using the filling and repairing method.
Further, the method of filling repair uses reactive ion deposition, and the method of removing repair uses an etching process or focused ion beam bombardment.
Further, before the step of obtaining the image of the mask pattern corresponding to the defect position of the mask pattern and the image of the corresponding position of the normal mask pattern, the method further comprises the following steps: and sending the photoetching mask plate with the mask pattern defects into a mask pattern defect repairing machine.
Further, the mask defect image and the normal mask image are SEM images of corresponding positions of the mask pattern and the normal mask pattern corresponding to the mask pattern defect position shot on the same photoetching mask plate.
Further, in the step of reducing the mask defect pattern or the pixels of the normal mask pattern, if the defect of the lithography mask is to be repaired by using a filling repair method, the pixels of the mask defect pattern are reduced to reduce the critical dimension of the mask defect pattern and keep the critical dimension of the normal mask pattern unchanged, and if the defect of the lithography mask is to be repaired by using the removal repair method, the pixels of the normal mask pattern are reduced to reduce the critical dimension of the normal mask pattern and keep the critical dimension of the mask defect pattern unchanged.
Further, the mask defect pattern and the normal mask pattern both comprise a blank area and an area filled in the outline, and when the pixels of the mask defect pattern or the normal mask pattern are reduced, only the pixels of the area filled in the outline are reduced, and the pixels of the blank area are kept unchanged.
Further, the geometry format is a graphic design system format.
Furthermore, the photoetching mask plate comprises a binary photoetching mask plate and a phase shift photoetching mask plate.
The repairing method of the invention reduces the pixels of the mask defect graph or the normal mask graph to correspondingly reduce the size of the mask defect graph or the normal mask graph, enlarges different areas between the mask defect graph and the normal mask graph, wherein the different areas are defect areas, and further easily identifies and positions the position of the defect area.
Drawings
The following drawings of the invention are included to provide a further understanding of the invention. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
In the drawings:
FIGS. 1A-1D are schematic diagrams illustrating steps associated with a method for repairing a mask pattern defect according to an embodiment of the present invention;
FIGS. 2A-2D are schematic diagrams illustrating steps associated with a method for repairing a mask pattern defect according to another embodiment of the present invention;
FIG. 3 is a diagram illustrating a defect area located in an embodiment of the present invention;
FIG. 4 is a process flow diagram of a method for repairing a mask pattern defect according to an embodiment of the present invention.
Detailed Description
In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the invention.
It is to be understood that the present invention may 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, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. Like reference numerals refer to like elements throughout.
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 and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.
Spatial relational terms such as "under," "below," "under," "above," "over," and the like may be used herein for convenience in describing the relationship of one element or feature 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, then 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. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial descriptors used herein interpreted accordingly.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to 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. As used herein, the term "and/or" includes any and all combinations of the associated listed items.
Embodiments of the invention are described herein with reference to cross-sectional illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the invention. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments of the invention should not be limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an implanted region shown as a rectangle will typically have rounded or curved features and/or implant concentration gradients at its edges rather than a binary change from implanted to non-implanted region. Also, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface through which the implantation is performed. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of the present invention.
In order to provide a thorough understanding of the present invention, detailed steps will be set forth in the following description in order to explain the technical solutions proposed by the present invention. The following detailed description of the preferred embodiments of the invention, however, the invention is capable of other embodiments in addition to those detailed.
Example one
The current plate making process of the photoetching mask plate mainly comprises the following steps: firstly, depositing a photosensitive material chromium nitride-chromium oxynitride on a flat and smooth glass (or quartz) substrate by direct-current magnetron sputtering to form a chromium film substrate; then, uniformly coating a layer of photoresist or electron beam resist on the chromium film substrate to prepare a uniform-photoresist chromium plate, wherein the uniform-photoresist chromium plate is a photomask substrate which is an ideal photosensitive blank for manufacturing micro geometric figures; and finally, printing the miniature geometric figure converted from the original integrated circuit design layout on the photomask base plate by a photoetching plate making process, thereby completing the plate making process of the photoetching mask plate. Each of the miniature geometric figures on the lithography mask corresponds to an original integrated circuit design layout, and the miniature geometric figures are called mask figures. Thus, millions of mask patterns are printed on the photolithographic mask that are identical to the original integrated circuit design layout.
After the photolithography mask is manufactured, the photolithography mask needs to be placed into a mask pattern inspection machine for pattern defect inspection. The inspection machine detects the mask pattern defects on the photoetching mask plate, the photoetching mask plate with the mask pattern defects is sent to the mask pattern defect repairing machine for defect repairing, and because the minimum critical dimension of the mask plate is reduced to be below a 28nm node, the defect pattern and the normal pattern do not have enough different points, the repairing machine is difficult to position the position coordinates of the region to be repaired of the mask pattern defects, the mask pattern defects cannot be accurately repaired, and the quality of the photoetching mask plate is reduced.
In order to solve the problem existing in the mask pattern defect repair, the present invention provides a method for repairing a mask pattern defect, as shown in fig. 4, which mainly comprises the following steps:
in step S1, acquiring an SEM image of a mask pattern corresponding to a mask pattern defect position on the lithography mask and an SEM image of a normal mask pattern corresponding to a mask pattern defect position, where the SEM image of the mask pattern corresponding to the mask pattern defect position is the mask defect image and the SEM image of the normal mask pattern corresponding to the normal mask pattern position is the normal mask image;
in step S2, extracting edge features of the mask defect image and the normal mask image, and converting the edge features into a geometric pattern format for storage, thereby obtaining an initial mask defect pattern and an initial normal mask pattern;
in step S3, filling blank areas in the edge profiles of the initial mask defect pattern and the initial normal mask pattern, thereby forming a mask defect pattern and a normal mask pattern;
in step S4, reducing the pixels of the mask defect pattern or the normal mask pattern to correspondingly reduce the size of the mask defect pattern or the normal mask pattern, thereby obtaining an intermediate mask defect pattern or an intermediate normal mask pattern, respectively;
in step S5, extracting edge features of the intermediate mask defect pattern or the intermediate normal mask pattern, and converting the edge features into a geometric pattern format for storage, thereby obtaining an edge contour pattern of the intermediate mask defect pattern or an edge contour pattern of the intermediate normal mask pattern;
in step S6, performing an overlap comparison between the edge contour pattern of the intermediate mask defect pattern and the initial normal mask pattern, or performing an overlap comparison between the edge contour pattern of the intermediate normal mask pattern and the initial mask defect pattern, and identifying an un-overlapped region, which is a defect region, so as to locate a position of a defect in the lithography mask;
in step S7, the defect on the photolithography mask is repaired.
According to the repairing method, the size of the mask defect graph or the normal mask graph is correspondingly reduced by reducing the pixels of the mask defect graph or the normal mask graph, different areas between the mask defect graph and the normal mask graph are enlarged, the different areas are defect areas, and then the positions of the defect areas are easily identified and positioned.
The method for repairing a mask pattern defect according to the present invention is described in detail with reference to fig. 1A-1D, fig. 2A-2D, and fig. 3 and 4, wherein fig. 1A-1D illustrate schematic diagrams obtained from the related steps of the method for repairing a mask pattern defect according to an embodiment of the present invention; FIGS. 2A-2D are schematic diagrams illustrating steps associated with a method for repairing a mask pattern defect according to another embodiment of the present invention; FIG. 3 is a diagram illustrating a defect area located in an embodiment of the present invention; FIG. 4 is a process flow diagram of a method for repairing a mask pattern defect according to an embodiment of the present invention.
First, a finished photolithography mask is provided, wherein the photolithography mask may be any type of mask known to those skilled in the art, for example, the photolithography mask may be a binary photolithography mask or a phase shift photolithography mask, etc.
And then, detecting the photoetching mask plate through a photoetching mask plate inspection machine table, determining the photoetching mask plate with the defects, and preliminarily judging whether to fill and repair or remove and repair the defects of the mask patterns on the photoetching mask plate.
As shown in fig. 1A and fig. 2A, specifically, the surface of the lithographic mask may be scanned by a high resolution microscope or an inspection machine, so as to obtain an SEM image of a mask pattern corresponding to a mask pattern defect position on the lithographic mask and an SEM image of a normal mask pattern corresponding to a mask pattern defect position, where the mask pattern image corresponding to a mask pattern defect position is a mask defect image (as shown in fig. 1A and fig. 2A (a)), and the normal mask pattern image corresponding to a normal mask pattern position is a normal mask image (as shown in fig. 1A and fig. 2A (b)), that is, a reference image.
Since there are many identical mask patterns identical to the original integrated circuit design layout pattern on the same lithographic mask, and only one or a few defective mask patterns are included, in one embodiment, one of the mask patterns without mask pattern defects (i.e., the normal mask pattern) is selected from the lithographic mask as the reference pattern. That is, another SEM image of a normal mask pattern without mask pattern defects is taken from the same photomask by SEM as a reference image. That is, the mask defect image and the normal mask image are SEM images of corresponding positions of the mask pattern and the normal mask pattern corresponding to the mask pattern defect position photographed on the same photolithography mask.
In one example, a method of inspecting the photolithographic reticle includes: and if the mask defect image comprises a concave part defect compared with the normal mask image, the concave part defect refers to that the mask defect image lacks a non-light-transmitting layer in a concave part region compared with the normal mask image, so that the concave part defect needs to be repaired by the filling repair method.
And then, sending the photoetching mask plate with the mask pattern defects into a mask pattern defect repairing machine.
For example, the repair machine may include a computer system, and an image processing program installed in the computer system, and the image processing program may perform processes of extracting edge features, filling, editing pixels, and the like on the received mask defect image and normal mask image.
Next, as shown in fig. 1B and fig. 2B, using a graph processing program on a repairing machine to extract edge features of the mask defect image and the normal mask image, and converting the edge features into a geometric graph format for storage, so as to obtain an initial mask defect image and an initial normal mask image, where the edge feature extraction method is an edge feature extraction method that is familiar to those skilled in the art. In one embodiment, the geometry format is a GDS format. One skilled in the art may also store edge feature data in other geometric formats.
And then filling the blank regions in the edge profiles of the initial mask defect pattern and the initial normal mask pattern to form a mask defect pattern and a normal mask pattern, and those skilled in the art can fill the blank regions in the edge profiles by using a common filling method, such as the mask defect pattern formed after filling shown in fig. 1B, and the normal mask pattern formed after filling shown in fig. 2B.
And then, reducing the pixels of the mask defect graph or the normal mask graph to correspondingly reduce the size of the mask defect graph or the normal mask graph so as to respectively obtain a middle mask defect graph or a middle normal mask graph, then, extracting the edge characteristics of the middle mask defect graph or the middle normal mask graph, converting the edge characteristics into a geometric graph format, and storing the geometric graph format so as to obtain the edge outline graph of the middle mask defect graph or the edge outline graph of the middle normal mask graph.
The pattern is composed of a plurality of black and white dots which have different sizes and different light and shade and are arranged according to a certain rule. These black and white dots are called pixels or pixels. Which is the smallest basic unit that makes up a graph. The mask defect pattern and the normal mask pattern are an aggregate of a lot of pixels, so that the critical dimensions of the mask defect pattern and the normal mask pattern can be correspondingly reduced by reducing the pixels of the mask defect pattern and the normal mask pattern, wherein the pixels can be edited by a graphic processing program on a repairing machine, namely, the pixel parameters in a control menu (recipe) of the corresponding pattern are modified.
Specifically, in an example, fig. 1C shows a schematic diagram of a defect pattern of an intermediate mask, and when repairing a defect of the photolithography mask is scheduled to be performed by using a filling repair method, pixels of the defect pattern of the mask are adjusted to reduce the pixels, so that a critical dimension of the defect pattern of the mask is reduced, thereby obtaining the defect pattern of the intermediate mask; while maintaining the critical dimensions of the normal mask pattern unchanged. The intermediate mask defect pattern is a region filled in the mask defect pattern including a blank region and an outline, and when pixels of the mask defect pattern are reduced, only the pixels of the region filled in the outline are reduced, and the pixels of the blank region are kept unchanged. The actual value of the adjustment pixel can be reasonably selected according to the size of the specific mask, for example, 1 to 10 unit pixels can be reduced, so that the size of the mask defect pattern is reduced in proportion.
Next, as shown in fig. 1D, the edge feature of the intermediate mask defect pattern is extracted, and is converted into a geometric pattern format to be stored, so as to obtain an edge profile pattern of the intermediate mask defect pattern, where the edge feature extraction method is a conventional edge feature extraction method for those skilled in the art. In one embodiment, the geometry format is a GDS format. One skilled in the art may also store edge feature data in other geometric formats.
Subsequently, as shown in fig. 3, the edge profile pattern of the intermediate mask defect pattern and the initial normal mask pattern are subjected to overlap comparison, and an un-overlapped region is identified, wherein the un-overlapped region is a defect region, so as to position the position of the defect in the lithography mask, wherein the position of the defect in the lithography mask can be positioned by obtaining the position coordinate of the defect region. The method for comparing the edge profile pattern of the intermediate mask defect pattern with the initial normal mask pattern in an overlapping manner may be visual observation or automatic defect detection, or a combination of the two methods.
The initial normal mask pattern is a pattern obtained by extracting the edge features of the normal mask image in the previous step.
In this step, the edge profile pattern of the intermediate mask defect pattern is a reduced mask defect pattern, so that when compared with the initial normal mask pattern, the difference between the two patterns is enlarged, that is, the different points are the non-overlapped areas of the two patterns, that is, the area is a defect area, and since the different points are enlarged, that is, the different points are the recess defects, the different points are easily detected automatically by the repairing machine, and further, information such as the coordinate position of the defect is output.
In another example, as shown in fig. 2C and 2D, if it is predetermined to repair the defect of the lithography reticle by using the method of removing and repairing, and as shown in fig. 2C, which is a schematic diagram of the normal mask pattern, only the pixels of the normal mask pattern are reduced, so as to reduce the critical dimension of the normal mask pattern, thereby obtaining the normal mask pattern, and keeping the critical dimension of the mask defect pattern unchanged. The intermediate normal mask pattern is a normal mask pattern including a blank area and an area filled in the outline, and when the pixels of the normal mask pattern are reduced, only the pixels of the area filled in the outline are reduced, and the pixels of the blank area are kept unchanged, wherein the value of the actually adjusted pixels can be reasonably selected according to the size of a specific mask plate, for example, 1 to 10 unit pixels can be reduced, so that the size of the normal mask pattern is proportionally reduced.
Next, as shown in fig. 2D, the edge feature of the intermediate normal mask pattern is extracted, and is converted into a geometric form for storage, so as to obtain an edge contour pattern of the intermediate normal mask pattern, where the edge feature extraction method is a conventional edge feature extraction method for those skilled in the art. In one embodiment, the geometry format is a GDS format. One skilled in the art may also store edge feature data in other geometric formats.
Finally, referring to fig. 3, the edge profile pattern of the middle normal mask pattern and the initial mask defect pattern are subjected to overlap comparison, and an un-overlapped area is identified, wherein the un-overlapped area is a defect area, so that the position of the defect in the lithography mask is positioned. The position of the defect in the photoetching mask can be positioned by acquiring the position coordinates of the defect area. The method for comparing the edge profile pattern of the middle normal mask pattern with the initial mask defect pattern in an overlapping manner may be visual observation or automatic defect detection, or a combination of the two methods.
The initial mask defect pattern is a pattern obtained by extracting edge features of the mask defect image in the previous step.
In the foregoing steps, it is determined that the mask defect is a protrusion, that is, the mask defect has a protrusion in a local area of the mask defect pattern, and the edge profile pattern of the middle normal mask pattern is a reduced normal mask pattern, so that compared with the initial mask defect pattern, the difference between the two patterns is enlarged, that is, the size of the protrusion is enlarged, and thus the protrusion is easily detected by the repairing machine automatically, and information such as the coordinate position of the protrusion is output.
And finally, repairing the defects on the corresponding photoetching mask according to the position shapes of the defects positioned in the previous step. And a reasonable repairing mode can be selected according to different defect types.
For example, when the defect is a protrusion, the protrusion corresponds to an extra opaque layer on the mask, and the material of the protrusion may be chromium or other impurities, and the protrusion is removed by a removal repair method, where the removal repair method may be any method known to those skilled in the art, for example, the removal repair method may use an etching process or focused ion beam bombardment, and the etching process may be a dry etching process such as laser etching, plasma etching, and the like.
In one example, when the mask pattern defect on the photolithography mask is a recess, the recess is caused by the absence of the opaque layer, and the like, and the opaque material needs to be refilled in the recess region to repair the recess defect.
There are many ways to fill the recesses or remove the protrusions, and the method is not limited to the method exemplified in the present embodiment.
According to the repairing method, the size of the mask defect graph or the normal mask graph is correspondingly reduced by reducing the pixels of the mask defect graph or the normal mask graph, the different area between the mask defect graph and the normal mask graph is enlarged, the different area is the defect area, and the position of the defect area is easily identified and positioned.
The present invention has been illustrated by the above embodiments, but it should be understood that the above embodiments are for illustrative and descriptive purposes only and are not intended to limit the invention to the scope of the described embodiments. Furthermore, it will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that many variations and modifications may be made in accordance with the teachings of the present invention, which variations and modifications are within the scope of the present invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (10)
1. A method for repairing mask pattern defects is characterized by comprising the following steps:
acquiring an SEM image of a mask pattern corresponding to a mask pattern defect position on a photoetching mask plate and an SEM image of a normal mask pattern corresponding to the mask pattern defect position, wherein the SEM image of the mask pattern corresponding to the mask pattern defect position is the mask defect image, and the SEM image of the normal mask pattern corresponding to the normal mask pattern position is the normal mask image;
extracting edge features of the mask defect image and the normal mask image, converting the edge features into a geometric figure format, and storing the geometric figure format to obtain an initial mask defect figure and an initial normal mask figure;
filling blank areas in the edge profiles of the initial mask defect pattern and the initial normal mask pattern to form a mask defect pattern and a normal mask pattern;
reducing the pixels of the mask defect graph or the normal mask graph to correspondingly reduce the size of the mask defect graph or the normal mask graph, so as to respectively obtain a middle mask defect graph or a middle normal mask graph;
extracting edge features of the intermediate mask defect graph or the intermediate normal mask graph, converting the edge features into a geometric graph format, and storing the geometric graph format so as to obtain an edge outline graph of the intermediate mask defect graph or an edge outline graph of the intermediate normal mask graph;
performing overlapping comparison on the edge outline graph of the intermediate mask defect graph and the initial normal mask graph, or performing overlapping comparison on the edge outline graph of the intermediate normal mask graph and the initial mask defect graph, and identifying an un-overlapped area, wherein the un-overlapped area is a defect area, so as to position the position of a defect in the photoetching mask plate;
and repairing the defects on the photoetching mask.
2. The repair method as set forth in claim 1, further comprising, before the step of reducing the pixels of the mask defect pattern or the normal mask pattern, the steps of: and detecting the photoetching mask plate to preliminarily judge whether the defects of the mask pattern on the photoetching mask plate are filled and repaired or removed and repaired.
3. The repair method of claim 2, wherein the method of inspecting the photolithographic reticle comprises:
and performing overlapping comparison on the mask defect image and the normal mask image, if the mask defect image comprises a bulge defect compared with the normal mask image, removing and repairing the bulge defect by using the removing and repairing method, and if the mask defect image comprises a recess defect compared with the normal mask image, repairing the recess defect by using the filling and repairing method.
4. The repair method of claim 3 wherein the method of fill repair uses reactive ion deposition and the method of strip repair uses an etching process or focused ion beam bombardment.
5. The repair method according to claim 1, wherein, before the step of obtaining the image of the mask pattern corresponding to the defective position of the mask pattern and the image of the corresponding position of the normal mask pattern, the method further comprises the steps of: and sending the photoetching mask plate with the mask pattern defects into a mask pattern defect repairing machine.
6. The repair method according to claim 1, wherein the mask defect image and the normal mask image are SEM images of corresponding positions of the mask pattern and the normal mask pattern corresponding to the mask pattern defect position photographed on the same photolithography mask.
7. The repairing method according to claim 2 or 3, wherein in the step of reducing the pixels of the mask defect pattern or the normal mask pattern, if the defect of the photolithography mask is to be repaired by using a filling repairing method, the pixels of the mask defect pattern are reduced to reduce the critical dimension of the mask defect pattern and keep the critical dimension of the normal mask pattern unchanged; if the defect of the photoetching mask is repaired by the removing and repairing method, reducing the pixels of the normal mask pattern, reducing the key size of the normal mask pattern, and keeping the key size of the mask defect pattern unchanged.
8. The repair method according to claim 1, wherein the mask defect pattern and the normal mask pattern each include a blank region and a region filled in the outline, and when the pixels of the mask defect pattern or the normal mask pattern are reduced, only the pixels of the region filled in the outline are reduced, and the pixels of the blank region are kept unchanged.
9. The repair method according to claim 1, wherein the geometric figure format is a graphic design system format.
10. The method of claim 1, wherein the lithography reticle comprises a binary lithography reticle and a phase shift lithography reticle.
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| CN110653494B (en) * | 2018-06-29 | 2021-01-01 | 上海微电子装备（集团）股份有限公司 | Laser repairing device and repairing method |
| CN110490864B (en) * | 2019-08-22 | 2021-09-21 | 易思维（杭州）科技有限公司 | Self-adaptive defect detection method for image |
| CN110836905A (en) * | 2019-11-13 | 2020-02-25 | 上海华力集成电路制造有限公司 | Failure analysis method for automatically identifying physical defects of chip |
| CN112418033B (en) * | 2020-11-11 | 2024-05-03 | 广州数鹏通科技有限公司 | Landslide slope surface segmentation recognition method based on mask rcnn neural network |
| CN112635348B (en) * | 2020-12-16 | 2022-07-19 | 华虹半导体(无锡)有限公司 | Method for establishing mask defect detection program |
| CN112862696A (en) * | 2020-12-31 | 2021-05-28 | 深圳市路维光电股份有限公司 | Mask repair control method and device and computer readable storage medium |
| CN114564908A (en) * | 2022-01-25 | 2022-05-31 | 深圳晶源信息技术有限公司 | Design layout defect repairing method, storage medium and device |
| CN116030047B (en) * | 2023-03-24 | 2023-05-30 | 四川中星电子有限责任公司 | Method for identifying mask qualification in capacitor process |
| CN117170181B (en) * | 2023-11-01 | 2024-01-26 | 合肥晶合集成电路股份有限公司 | Mask cleaning method, device and computer readable storage medium |
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| CN104317159A (en) * | 2010-03-03 | 2015-01-28 | 中芯国际集成电路制造(上海)有限公司 | Mask graphic defect detection method and mask graphic defect detection system for |
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