CN114911130A - Photomask, detection method, device, equipment and medium thereof - Google Patents

Abstract

The embodiment of the disclosure relates to a photomask and a detection method, a detection device, equipment and a medium thereof, wherein the photomask comprises a photomask body and a light calibration mark arranged on the photomask body; the photomask body comprises a substrate made of a first material, a first pattern layer made of a second material and a second pattern layer made of a third material which are sequentially overlapped along a first direction, wherein the first pattern layer and the second pattern layer are used for limiting a transfer pattern of the photomask together; the light calibration mark comprises a first mark pattern made of a first material, a second mark pattern made of a second material and a third mark pattern made of a third material which are sequentially arranged along a second direction; wherein the first direction is perpendicular to the second direction. The embodiment of the disclosure improves the efficiency and the precision of defect detection on the photomask, thereby improving the yield and the reliability of the prepared semiconductor product.

Description

Photomask and detection method, device, equipment and medium thereof

Technical Field

The present disclosure relates to the field of semiconductor technologies, and in particular, to a photomask, and a method, an apparatus, a device, and a medium for detecting the photomask.

Background

The mask is a carrier for image transmission, designed circuit patterns are exposed on the photosensitive adhesive through electronic laser equipment, exposed areas can be developed to form circuit patterns, the circuit patterns become masks similar to the exposed negative films, then the masks are applied to projection positioning of integrated circuits, and photoetching is carried out on the projected circuits through an integrated circuit photoetching machine.

However, various defects are inevitably formed in the mask manufacturing process, and the mask needs to be inspected by an inspection machine. The traditional photomask detection method has long detection period and low detection efficiency, and influences the yield and reliability of subsequent semiconductor products.

Disclosure of Invention

Accordingly, there is a need for a photomask, and a method, an apparatus, a device and a medium for inspecting the photomask, which can improve the efficiency and accuracy of inspecting defects of the photomask, thereby improving the yield and reliability of semiconductor products.

In order to achieve the above and other objects, a first aspect of the embodiments of the present disclosure provides a mask, including a mask body and a light alignment mark disposed on the mask body; the photomask body comprises a substrate made of a first material, a first pattern layer made of a second material and a second pattern layer made of a third material which are sequentially overlapped along a first direction, wherein the first pattern layer and the second pattern layer are used for limiting a transfer pattern of the photomask together; the light calibration mark comprises a first mark pattern made of a first material, a second mark pattern made of a second material and a third mark pattern made of a third material which are sequentially arranged along a second direction; wherein the first direction is perpendicular to the second direction.

In the photomask in the above embodiment, the light alignment mark including the first mark pattern made of the first material, the second mark pattern made of the second material, and the third mark pattern made of the third material sequentially arranged along the second direction is disposed on the photomask body; the material of the first mark pattern is the same as that of the substrate and is a first material; the second mark pattern is made of the same material as the first pattern layer and is made of the second material, and the third mark pattern is made of the same material as the second pattern layer and is made of the third material, so that materials corresponding to the first material, the second material and the third material which are different can be found on the light calibration mark; because the adverse effect that the areas outside the target photomask detection area possibly interfere with the detection light is avoided, the photomask detection precision is effectively improved by the embodiment of the disclosure.

According to some embodiments of the present disclosure, the first mark pattern and the substrate are located on the same layer, the second mark pattern and the first pattern layer are located on the same layer, and the third mark pattern and the second pattern layer are located on the same layer, so as to effectively improve the targeting and efficiency of obtaining the first mark pattern, the second mark pattern and the third mark pattern in the photomask detection process, and avoid the problems of labor hour waste and high requirements for related experience of workers due to random obtaining of the three mark patterns, i.e., the first mark pattern, the second mark pattern and the third mark pattern.

According to some embodiments of the present disclosure, at least one of the first mark pattern, the second mark pattern, and the third mark pattern is rectangular in orthographic projection on the surface of the substrate, so that alignment is performed according to two perpendicular sides of the rectangle, and efficiency and accuracy of alignment using the mark patterns are improved.

According to some embodiments of the present disclosure, the length or width of the rectangle is in the range of 480nm-520nm to meet the size requirements of current conventional chip sizes for light alignment marks.

According to some embodiments of the present disclosure, the size of the orthographic projection of the first mark pattern on the surface of the substrate, the size of the orthographic projection of the second mark pattern on the surface of the substrate, and the size of the orthographic projection of the third mark pattern on the surface of the substrate are the same, so as to reduce the complexity of mark pattern preparation, effectively improve the targeting and efficiency of obtaining the first mark pattern, the second mark pattern, and the third mark pattern in the photomask detection process, and avoid the problems of labor hour waste and high requirements on related experience of workers due to random obtaining of the three mark patterns, namely, the first mark pattern, the second mark pattern, and the third mark pattern.

According to some embodiments of the present disclosure, the orthographic projection of the first mark pattern on the surface of the substrate, the orthographic projection of the second mark pattern on the surface of the substrate, and the orthographic projection of the third mark pattern on the surface of the substrate are both squares, so that alignment is performed according to two perpendicular sides of the squares, and the efficiency and accuracy of alignment by using the mark patterns are improved; meanwhile, the goal and efficiency of acquiring the first mark pattern, the second mark pattern and the third mark pattern in the photomask detection process are effectively improved.

According to some embodiments of the present disclosure, the light alignment mark is located within a scribe line region of the reticle body; the influence of the optical alignment mark on the target pattern transferred by the photomask is avoided, and the precision of transferring the target pattern to the wafer by using the photomask is improved.

According to some embodiments of the present disclosure, the first material, the second material, and the third material are different and are selected from one of quartz, molybdenum silicide, and chrome alloy, so as to meet the inspection requirements of the current standard mask.

A second aspect of the embodiments of the present disclosure provides a method for detecting whether any photomask in any of the embodiments of the present disclosure has a defect; the method comprises the following steps: projecting a target light beam to a target area of the reticle, the target area having the light alignment mark disposed therein; acquiring real-time calibration parameters of the target area to the target light beam; and comparing the real-time calibration parameters with corresponding preset standard parameters in a standard database, and judging whether the photomask has defects according to the comparison result so as to improve the efficiency and the precision of defect detection on the photomask.

According to some embodiments of the present disclosure, the target beam comprises a first beam of light of a first wavelength, a second beam of light of a second wavelength, and a third beam of light of a third wavelength; the projecting a target beam to a target area of the reticle includes: projecting a first light beam at a first wavelength onto a first pattern of marks within the target area; projecting a second light beam at a second wavelength onto a second pattern of marks within the target area; a third beam of light of a third wavelength is projected onto a third pattern of marks in the target area. Because the target area comprises the first mark graph, the second mark graph and the third mark graph which are made of three different materials, the time spent on searching the three materials is effectively shortened, and the efficiency and the precision of defect detection of the photomask are improved.

According to some embodiments of the present disclosure, the real-time calibration parameters include a first calibration parameter, a second calibration parameter, and a third calibration parameter; the acquiring real-time calibration parameters of the target area to the target beam comprises: acquiring a first calibration parameter of the first mark pattern to the first light beam; acquiring a second calibration parameter of the second mark pattern to the second light beam; and acquiring a third calibration parameter of the third mark pattern to the third light beam.

According to some embodiments of the present disclosure, the preset standard parameters include a first standard parameter, a second standard parameter, and a third standard parameter; the comparing the real-time calibration parameter with the corresponding preset standard parameter and judging whether the photomask has defects according to the comparison result comprises the following steps: if the first calibration parameter is greater than or equal to the first standard parameter, determining that the photomask has a first defect; if the second calibration parameter is greater than or equal to the second standard parameter, determining that a second defect exists in the photomask; and if the third calibration parameter is greater than or equal to the third standard parameter, judging that the photomask has a third defect.

According to some embodiments of the present disclosure, the reticle inspection method further comprises: and projecting light beams with different wavelengths onto different mark patterns in the target area, respectively measuring and calculating reflectivity and transmissivity data, and storing the data into the standard database.

A third aspect of the embodiments of the present disclosure provides a mask inspection apparatus, configured to inspect whether any mask in any of the embodiments of the present disclosure has a defect; the device comprises a projection module and a judgment module, wherein the projection module is used for projecting a target light beam to a target area of the photomask, and the light calibration mark is arranged in the target area; the judging module is used for acquiring real-time calibration parameters of the target area to the target light beam, comparing the real-time calibration parameters with corresponding preset standard parameters in a standard database, and judging whether the photomask has defects according to a comparison result. Because the target area comprises the first mark graph, the second mark graph and the third mark graph which are made of three different materials, the time spent on searching the three materials is effectively shortened, and the efficiency and the precision of defect detection of the photomask are improved.

A fourth aspect of the embodiments of the present disclosure provides a mask inspection apparatus, including a memory and a processor, where the memory stores a computer program, and the processor implements the steps of any mask inspection method in the embodiments of the present disclosure when executing the computer program.

A fifth aspect of the embodiments of the present disclosure provides a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the steps of any of the methods of mask inspection in the embodiments of the present disclosure.

In the photomask detection method, the photomask detection device, the photomask detection equipment and the photomask detection medium in the embodiments, the materials corresponding to the first material, the second material and the third material can be found on one optical calibration mark of the photomask body, and compared with the traditional photomask detection method, the detection method needs to search for the materials corresponding to the three materials outside the target photomask detection area, the detection target is stronger, and the detection efficiency is higher; because the adverse effect that the areas outside the target photomask detection area possibly interfere the detection light is avoided, the precision of photomask detection is effectively improved. Because the target area comprises the first mark graph, the second mark graph and the third mark graph of three different materials, the time spent on searching the three materials is effectively shortened.

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 the drawings without creative efforts.

FIG. 1 is a schematic top view of a mask according to an embodiment of the present disclosure;

FIG. 2 is a schematic top view of a light alignment mark of a mask according to an embodiment of the present disclosure;

FIG. 3 is a schematic cross-sectional view of the mask of FIG. 1 taken along direction BB';

FIG. 4 is a schematic flow chart illustrating a mask inspection method according to an embodiment of the present disclosure;

FIG. 5 is a schematic flow chart illustrating a mask inspection method according to another embodiment of the present disclosure;

FIG. 6a is a wafer prepared using a mask provided in an embodiment of the present disclosure;

FIG. 6B is a schematic enlarged partial view B corresponding to the rectangular frame area in FIG. 6 a;

FIG. 6c is a preset image corresponding to FIG. 6 b;

FIG. 7 is a schematic flow chart illustrating a mask inspection method according to yet another embodiment of the present disclosure;

FIG. 8 is a block diagram of a mask inspection device according to an embodiment of the present disclosure;

FIG. 9 is a block diagram of a mask inspection device according to another embodiment of the present disclosure;

FIG. 10 is a block diagram of a mask inspection apparatus according to still another embodiment of the present disclosure.

Description of reference numerals:

100. a photomask; 10. a mask body; 20. a light alignment mark; 11. a substrate; 12. a first pattern layer; 13. a second pattern layer; 21. a first pattern of marks; 22. a second pattern of marks; 23. a third pattern of marks; 300. a mask inspection device; 31. an image acquisition module; 32. a comparison module; 321. a gray scale value acquisition unit; 322. a gray scale difference value acquisition unit; 323. a judgment unit; 41. a projection module; 42. and a judging module.

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 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, doping type or section from another element, component, region, layer, doping type 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," "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.

Forming a pattern on the semiconductor by using a photo-etching technique during the process of manufacturing the semiconductor chip by the photomask; to copy the pattern onto the wafer, the image must be copied onto the photo by the principle of a photomask, similar to that used to copy a photo from a negative film during photo development. The photomask generally uses quartz glass as a substrate, a layer of metal chromium and photosensitive resist is plated on the quartz glass, a designed circuit pattern is exposed on the photosensitive resist through electronic laser equipment, an exposed area can be developed, the circuit pattern is formed on the metal chromium to form a photomask similar to an exposed negative, then the photomask is applied to projection positioning of an integrated circuit, and photoetching is carried out on the projected circuit through an integrated circuit photoetching machine, and the production and processing procedures generally comprise: exposing, developing, removing photosensitive resist and photoetching.

In a conventional photomask detection method, before each photomask leaves a factory, a corresponding detection process needs to be established, different material film layers in the photomask are found before detection, and the film layers are scanned respectively to calibrate a scanning light source of a detection machine, for example, a film layer where quartz glass of the photomask is located needs to be calibrated. If at least three films made of different materials are found in the photomask in a random mode, then a scanning light source of a detection machine is calibrated, and a large amount of time is spent by a relevant engineer; moreover, if the scanning light source is irradiated to a region other than the target detection region, for example, a region other than a Pellicle (Pellicle) of the mask, during the light source calibration process, the scanning light may be interfered, accuracy may be affected, and the mask detection result may be misjudged.

As an example, referring to fig. 1, in an embodiment of the present disclosure, a mask 100 is provided, which includes a mask body 10 and a light alignment mark 20 disposed on the mask body 10; the mask body 10 includes a substrate 11 of a first material, a first pattern layer 12 of a second material, and a second pattern layer 13 of a third material, which are sequentially stacked along a first direction, such as a thickness/height direction, wherein the first pattern layer 12 and the second pattern layer 13 are used to jointly define a transfer pattern of the mask; the light alignment mark 20 comprises a first mark pattern 21 made of a first material, a second mark pattern 22 made of a second material and a third mark pattern 23 made of a third material which are sequentially arranged along a second direction; wherein the first direction is perpendicular to the second direction.

In particular, typical defects, such as bridging, defocusing, etc., inevitably occur during photolithography to prepare the photomask, which affects the yield and pattern accuracy of the prepared photomask to various degrees, and therefore, a defect detection step after photolithography is indispensable. Before the photomask is subjected to defect detection, films made of different materials in the photomask need to be found, and a scanning light source of a detection machine is calibrated. For example, an Optical Microscope (OM) in a defect inspection machine emits incident light to a target mask, receives reflected light reflected from the target mask, and determines whether the surface of the target mask has a photoresist according to the surface absorbance of the target mask, which is the difference between the incident light amount and the reflected light amount. If the target mask is judged to have the photoresist, the machine stops the defect detection, and the engineer calibrates the scanning light source of the detection machine. In the mask 100 of the present disclosure, the light alignment mark 20 including the first mark pattern 21 made of the first material, the second mark pattern 22 made of the second material, and the third mark pattern 23 made of the third material sequentially arranged along the second direction is disposed on the mask body 10; the first material, the second material and the third material are different; the material of the first mark pattern 21 is the same as that of the substrate 11, and both the first mark pattern and the substrate are made of a first material; the second mark pattern 22 is made of the same material as the first pattern layer 12 and is made of the second material, and the third mark pattern 23 is made of the same material as the second pattern layer 13 and is made of the third material, so that the materials corresponding to the first material, the second material and the third material can be found on one light alignment mark 20, and compared with the traditional photomask detection method, the detection method needs to search materials corresponding to the three materials outside a target photomask detection area, the detection target is stronger, and the detection efficiency is higher; because the adverse effect that the areas outside the target photomask detection area possibly interfere with the detection light is avoided, the photomask detection precision is effectively improved by the embodiment of the disclosure.

For example, please refer to fig. 2-3, wherein fig. 2 is a schematic top view of a mask according to an embodiment of the disclosure, and fig. 3 is a schematic cross-sectional structure of the mask along the direction BB' in fig. 1; a first direction perpendicular to the surface of the substrate 11, e.g. the oz direction, and a second direction parallel to the surface of the substrate 11, e.g. the ox direction; by arranging the first mark pattern 21 made of the first material, the second mark pattern 22 made of the second material and the third mark pattern 23 made of the third material in the light alignment mark 20 in a linear arrangement along a direction parallel to the surface of the substrate 11, for example, in an ox direction, the goal and efficiency of obtaining the first mark pattern 21, the second mark pattern 22 and the third mark pattern 23 in the photomask detection process can be effectively improved, and the problems of labor hour waste and high requirements on related experiences of workers due to random obtaining of the three mark patterns, namely the first mark pattern 21, the second mark pattern 22 and the third mark pattern 23, are avoided.

As an example, referring to fig. 2-3, the first material of the substrate 11 may be quartz, the second material of the first pattern layer 12 may be molybdenum silicide (MoSi), and the third material of the second pattern layer 13 may be chromium alloy. Because the photomask generally uses quartz glass as a substrate, a layer of metal chromium and photosensitive resist are plated on the substrate, the material of the photosensitive resist comprises molybdenum silicide, and the detection requirement of the current standard photomask can be met by arranging the light calibration mark and simultaneously comprising three materials of quartz, molybdenum silicide and chromium alloy. In the process of calibrating the scanning light source of the detection machine, the corresponding material can be directly searched in the light calibration mark 20, so that the detection target is stronger and the detection efficiency is higher; because the adverse effect that the areas outside the target photomask detection area possibly interfere with the detection light is avoided, the photomask detection precision is effectively improved by the embodiment of the disclosure.

As an example, referring to fig. 2-3, the first direction is, for example, the oz direction, and the second direction is, for example, the ox direction, which are perpendicular to each other, so as to avoid the situation that the detection precision is reduced due to uneven light irradiation during the defect scanning detection of the first mark pattern 21, the second mark pattern 22 and the third mark pattern 23 by the scanner.

As an example, with continuing reference to fig. 2-3, the first mark pattern 21 and the substrate 11 may be disposed on the same layer, the second mark pattern 22 and the first pattern layer 12 are disposed on the same layer, and the third mark pattern 23 and the second pattern layer 13 are disposed on the same layer, so as to effectively improve the targeting and efficiency of obtaining the first mark pattern 21, the second mark pattern 22 and the third mark pattern 23 during the mask inspection process, and avoid the problems of labor hour waste and high requirements for related experience of workers due to random obtaining of the three mark patterns, i.e., the first mark pattern 21, the second mark pattern 22 and the third mark pattern 23.

As an example, referring to fig. 2, at least one of the first mark pattern 21, the second mark pattern 22 and the third mark pattern 23 is rectangular in orthographic projection on the surface of the substrate 11, for example, the orthographic projection of the first mark pattern 21, the second mark pattern 22 and the third mark pattern 23 on the surface of the substrate 11 is rectangular, so that alignment is performed according to two perpendicular sides of the rectangle, and efficiency and accuracy of alignment performed by using the mark patterns are improved.

By way of example, with continued reference to fig. 2, at least one of the first mark pattern 21, the second mark pattern 22 and the third mark pattern 23 has a rectangular shape in a front projection on the surface of the substrate 11, and the length of the rectangular shape ranges from 480nm to 520nm, for example, the length of the rectangular shape may be 480nm, 490nm, 500nm, 510nm or 520nm, etc.; the width of the rectangle is in the range of 480nm-520nm, for example, the width of the rectangle may be 480nm, 490nm, 500nm, 510nm, 520nm, or the like. This embodiment can meet the current conventional chip size requirements for the size of the light alignment marks 20.

For example, referring to fig. 2, the orthogonal projection of the first mark pattern 21 on the surface of the substrate 11, the orthogonal projection of the second mark pattern 22 on the surface of the substrate 11, and the orthogonal projection of the third mark pattern 23 on the surface of the substrate 11 are all the same in size, so as to reduce the complexity of mark pattern preparation, effectively improve the targeting and efficiency of obtaining the first mark pattern 21, the second mark pattern 22, and the third mark pattern 23 during the mask inspection process, and avoid the problems of labor hour waste and high requirements on related experiences of workers due to random obtaining of the three mark patterns, i.e., the first mark pattern 21, the second mark pattern 22, and the third mark pattern 23.

As an example, with continued reference to fig. 2, the orthographic projection of the first mark pattern 21 on the surface of the substrate 11, the orthographic projection of the second mark pattern 22 on the surface of the substrate 11, and the orthographic projection of the third mark pattern 23 on the surface of the substrate 11 are both squares, so that the alignment is performed according to two perpendicular sides of the square, and the efficiency and the accuracy of the alignment performed by using the mark patterns are improved; meanwhile, the goal and efficiency of obtaining the first mark pattern 21, the second mark pattern 22 and the third mark pattern 23 in the mask inspection process are effectively improved.

For example, the first material, the second material, and the third material are different and are selected from one of quartz, molybdenum silicide, and chrome alloy, so as to meet the inspection requirements of the current standard mask.

Referring to FIG. 4, in some embodiments of the present disclosure, a method for inspecting a mask for defects is provided in any of the embodiments of the present disclosure; the method comprises the following steps:

step S210: projecting the target light beam to a target area of the photomask, wherein a light alignment mark is arranged in the target area;

step S220: acquiring real-time calibration parameters of a target area to a target light beam;

step S230: and comparing the real-time calibration parameters with corresponding preset standard parameters in a standard database, and judging whether the photomask has defects according to the comparison result.

Specifically, referring to fig. 4, since the target region of the mask includes the first mark pattern, the second mark pattern and the third mark pattern of three different materials, the time spent on searching the three materials is effectively reduced. In this embodiment, on one optical calibration mark of the mask body, the materials corresponding to the first material, the second material and the third material can be found, and compared with the conventional mask detection method in which the materials corresponding to the three materials need to be found outside the target mask detection area, the detection target is stronger and the detection efficiency is higher; because the adverse effect that the areas outside the target photomask detection area possibly interfere the detection light is avoided, the precision of photomask detection is effectively improved.

As an example, the target beam may be set to include a first beam of a first wavelength, a second beam of a second wavelength, and a third beam of a third wavelength; projecting the target beam onto the target area of the reticle in step S210 includes:

step S211: projecting a first light beam at a first wavelength onto a first pattern of marks within the target area;

step S212: projecting a second light beam at a second wavelength onto a second pattern of marks within the target area;

step S213: projecting a third beam of light at a third wavelength onto a third pattern of marks in the target area.

As an example, the real-time calibration parameters may be set to include a first calibration parameter, a second calibration parameter, and a third calibration parameter; in step S220, acquiring real-time calibration parameters of the target area to the target beam includes:

step S221: acquiring a first calibration parameter of the first mark pattern to the first light beam;

step S222: acquiring a second calibration parameter of the second mark pattern to the second light beam;

step S223: a third calibration parameter of the third mark pattern to the third light beam is obtained.

Specifically, a scanning light source of the calibration and detection machine can be controlled to emit a first light beam with a first wavelength, and the first light beam with the first wavelength is projected onto a first mark pattern in the target area; the method comprises the steps of obtaining a first calibration parameter of a first mark pattern to a first light beam with a first wavelength, comparing the first calibration parameter with a corresponding preset standard parameter in a standard database, and judging whether a photomask has defects according to a comparison result. Similarly, a second calibration parameter of the second mark pattern to a second light beam with a second wavelength is obtained, then the second calibration parameter is compared with a corresponding preset standard parameter in a standard database, and whether the photomask has defects is judged according to the comparison result; and comparing the third calibration parameter with a corresponding preset standard parameter in a standard database by acquiring a third calibration parameter of the third mark pattern to a third light beam with a third wavelength, and judging whether the photomask has defects according to the comparison result. In the embodiment, the three determined light beams are emitted and projected into the detection area at the determined position, and the obtained real-time calibration parameters are compared with the corresponding preset standard parameters in the standard database to judge whether the photomask has defects or not, so that the efficiency of detecting the defects of the photomask is effectively improved.

As an example, the preset standard parameters may be set to include a first standard parameter, a second standard parameter, and a third standard parameter; comparing the real-time calibration parameter with the corresponding preset standard parameter in step S230, and determining whether the photomask has a defect according to the comparison result, including:

step S231: if the first calibration parameter is larger than the first standard parameter, judging that the photomask has a first defect;

step S232: if the second calibration parameter is larger than the second standard parameter, judging that the photomask has a second defect;

step S233: and if the third calibration parameter is larger than the third standard parameter, judging that the photomask has a third defect.

Specifically, a scanning light source of the calibration and detection machine can be controlled to emit a first light beam with a first wavelength, and the first light beam with the first wavelength is projected onto a first mark pattern in the target area; the method comprises the steps of obtaining the reflectivity and the transmissivity data of a first mark pattern to a first light beam with a first wavelength, comparing the reflectivity with a corresponding standard reflectivity in a standard database, comparing the transmissivity with a corresponding standard transmissivity in the standard database, and judging whether a photomask has a first defect according to a comparison result. Similarly, the data of the reflectivity and the transmissivity of the second mark pattern to the second light beam with the second wavelength are obtained, then the reflectivity is compared with the corresponding standard reflectivity in the standard database, the transmissivity is compared with the corresponding standard transmissivity in the standard database, and whether the photomask has a second defect or not is judged according to the comparison result; and obtaining the reflectivity and transmissivity data of the third mark pattern to the third light beam with the third wavelength, then comparing the reflectivity with the corresponding standard reflectivity in the standard database, comparing the transmissivity with the corresponding standard transmissivity in the standard database, and judging whether the photomask has a third defect according to the comparison result.

According to some embodiments of the present disclosure, the target beam is a variable wavelength laser beam emitted by a tunable laser, which may have a wavelength of 160nm, 195nm, or 250 nm.

According to some embodiments of the present disclosure, the target light beam is a light beam emitted from a halogen light source, and the wavelength range may be adjusted by a filter to be 110nm to 1000nm, for example, the wavelength may be 110nm, 130nm, 150nm, 170nm, 180nm, 190nm, or 1000 nm.

According to some embodiments of the present disclosure, the real-time calibration parameter is compared with the corresponding preset standard parameter in step S230, and whether the photomask has a defect is determined according to the comparison result, and the determination rule may be:

if the difference between the first calibration parameter and the first standard parameter is more than or equal to 0.1%, judging that the photomask has a first defect; wherein the first wavelength may range from [800nm, 1000nm ];

if the difference between the second calibration parameter and the second standard parameter is more than or equal to 1%, judging that the photomask has a second defect; wherein the second wavelength may range from [160nm, 800 nm);

if the difference between the third calibration parameter and the third standard parameter is more than or equal to 3%, judging that the photomask has a third defect; wherein the third wavelength may be in the range of [110nm, 160 nm).

According to some embodiments of the present disclosure, light beams with different wavelengths may be projected onto different mark patterns in the target region, and reflectivity and transmissivity data may be measured and stored in the standard database.

Referring to FIG. 5, in some embodiments of the present disclosure, a method for inspecting a mask for defects is provided in any of the embodiments of the present disclosure; the method comprises the following steps:

step S310: obtaining a transfer image and a corresponding preset image of the surface of a bare chip, wherein the bare chip is obtained after pattern transfer is carried out on a wafer through a photomask;

step S320: and comparing the transferred image with the corresponding preset image, and judging whether the photomask has defects according to the comparison result.

For example, with continued reference to fig. 5, fig. 6a, fig. 6B, and fig. 6c, fig. 6a illustrates a wafer prepared according to a mask provided in an embodiment of the present disclosure, fig. 6B illustrates a partially enlarged schematic view B corresponding to a rectangular frame region in fig. 6a, and fig. 6c illustrates a predetermined image corresponding to fig. 6B, and by comparing the images in fig. 6B and fig. 6c, it can be determined that a curved frame region in fig. 6B is a defect region. In the embodiment, a computer can be used for acquiring a transfer image and a corresponding preset image of the surface of a bare chip, wherein the bare chip is obtained by transferring a pattern to a wafer through a photomask; and then comparing the transferred image with the corresponding preset image, and judging whether the photomask has defects according to the comparison result, thereby effectively improving the efficiency and the precision of defect detection of the photomask.

For example, referring to fig. 5 and 7, the step of comparing the transferred image with the corresponding default image in step S320 and determining whether the mask has defects according to the comparison result includes:

step S321, obtaining initial gray scale values of different positions on the transferred image and corresponding target gray scale values of different positions on the preset image;

step S322, obtaining the difference value between the initial gray-scale value and the target gray-scale value at the same position;

in step S323, if the absolute value of the difference is greater than or equal to the predetermined threshold, it is determined that the photomask has a defect.

Specifically, due to the defect of the photomask, the target image transferred to the wafer through the photomask is abnormal, the difference value between the initial gray-scale value and the target gray-scale value at the same position is obtained, whether the absolute value of the difference value is greater than or equal to the preset threshold value or not is judged, if yes, the existence of the defect of the photomask is judged, and the efficiency and the precision of defect detection of the photomask are effectively improved.

For example, referring to fig. 5 and 7, the step of comparing the transferred image with the corresponding predetermined image in step S320 and determining whether the mask has a defect according to the comparison result further includes:

in step S324, if the difference is within the predetermined accuracy range, it is determined that the photomask meets the requirement.

Specifically, if the precision of the target image transferred to the wafer through the photomask is within the preset precision range and meets the precision requirement of the target image transferred by the photomask, the photomask is judged to meet the detection requirement, and the precision of defect detection on the photomask is improved.

It should be understood that, although the steps in the flowcharts of fig. 4, 5 and 7 are shown in order as indicated by the arrows, the steps are not necessarily performed in order as indicated by the arrows. The steps are not performed in the exact order shown and described, and may be performed in other orders, unless explicitly stated otherwise. Moreover, although at least some of the steps in fig. 4, 5 and 7 may include multiple steps or multiple stages, the steps or stages are not necessarily performed at the same time, but may be performed at different times, the steps or stages are not necessarily performed in sequence, and may be performed alternately or alternatively with other steps or at least some of the other steps.

Referring to FIG. 8, in some embodiments of the present disclosure, a mask inspection apparatus 300 is provided for inspecting a mask for defects in any of the embodiments of the present disclosure; the device comprises an image acquisition module 31 and a comparison module 32, wherein the image acquisition module 31 is used for acquiring a transfer image and a corresponding preset image of the surface of a bare chip, and the bare chip is obtained by transferring a pattern to a wafer through a photomask; the comparison module 32 is configured to compare the transferred image with the corresponding preset image, and determine whether the photomask has a defect according to the comparison result, so as to improve the efficiency and accuracy of defect detection on the photomask.

As an example, referring to fig. 1-3, a mask for transferring a pattern to a wafer includes a mask body 10 and a light alignment mark 20 disposed on the mask body 10; the mask body 10 includes a substrate 11 of a first material, a first pattern layer 12 of a second material, and a second pattern layer 13 of a third material, which are sequentially stacked along a first direction, such as a thickness/height direction, wherein the first pattern layer 12 and the second pattern layer 13 are used to jointly define a transfer pattern of the mask; the light alignment mark 20 comprises a first mark pattern 21 made of a first material, a second mark pattern 22 made of a second material and a third mark pattern 23 made of a third material which are sequentially arranged along a second direction; wherein the first direction is oblique to the second direction. The first material, the second material and the third material are different; the material of the first mark pattern 21 is the same as that of the substrate 11, and both the first mark pattern and the substrate are made of a first material; the material of the second mark pattern 22 is the same as the material of the first pattern layer 12, and is the second material, and the material of the third mark pattern 23 is the same as the material of the second pattern layer 13, and is the third material, so that the material corresponding to the three different materials of the first material, the second material and the third material can be found on one light calibration mark 20, before the defect detection is carried out on the photomask, the different material film layers in the light calibration mark 20 are directly used, and the scanning light source of the detection machine is calibrated. The light alignment mark 20 is disposed in the scribe line of the mask, so as to prevent the light alignment mark 20 from affecting the target pattern transferred by the mask, and improve the precision of transferring the target pattern to the wafer by using the mask.

As an example, referring to fig. 2-3, the first material of the substrate 11 may be quartz, the second material of the first pattern layer 12 may be molybdenum silicide (MoSi), and the third material of the second pattern layer 13 may be chromium alloy. Because the photomask generally uses quartz glass as a substrate, a layer of metal chromium and photoresist are plated on the substrate, the material of the photoresist comprises molybdenum silicide, and the detection requirement of the current standard photomask can be met by arranging the light calibration mark and simultaneously comprising three materials of quartz, molybdenum silicide and chromium alloy. In the process of calibrating the scanning light source of the detection machine, the corresponding material can be directly searched in the light calibration mark 20, so that the detection target is stronger and the detection efficiency is higher; because the adverse effect that the areas outside the target photomask detection area possibly interfere with the detection light is avoided, the photomask detection precision is effectively improved by the embodiment of the disclosure.

As an example, referring to fig. 2-3, the first direction is, for example, the oz direction, and the second direction is, for example, the ox direction, which are perpendicular to each other, so as to avoid the situation that the detection precision is reduced due to uneven light irradiation during the defect scanning detection of the first mark pattern 21, the second mark pattern 22 and the third mark pattern 23 by the scanner.

As an example, with continuing reference to fig. 2-3, the first mark pattern 21 and the substrate 11 may be disposed on the same layer, the second mark pattern 22 and the first pattern layer 12 are disposed on the same layer, and the third mark pattern 23 and the second pattern layer 13 are disposed on the same layer, so as to effectively improve the targeting and efficiency of obtaining the first mark pattern 21, the second mark pattern 22 and the third mark pattern 23 during the mask inspection process, and avoid the problems of labor hour waste and high requirements for related experience of workers due to random obtaining of the three mark patterns, i.e., the first mark pattern 21, the second mark pattern 22 and the third mark pattern 23.

For example, referring to fig. 8, fig. 6a, fig. 6B and fig. 6c, fig. 6a illustrates a wafer prepared according to a mask provided in an embodiment of the present disclosure, fig. 6B illustrates a partially enlarged schematic view B corresponding to a rectangular frame region in fig. 6a, and fig. 6c illustrates a predetermined image corresponding to fig. 6B, and by comparing the images in fig. 6B and fig. 6c, it can be determined that a curved frame region in fig. 6B is a defect region. In the embodiment, a computer can be used for acquiring a transfer image and a corresponding preset image of the surface of a bare chip, wherein the bare chip is obtained by transferring a pattern to a wafer through a photomask; and then comparing the transferred image with the corresponding preset image, and judging whether the photomask has defects according to the comparison result, thereby effectively improving the efficiency and the precision of defect detection of the photomask.

For example, referring to fig. 9, the comparing module 32 includes a gray-scale value obtaining unit 321, a gray-scale difference value obtaining unit 322, and a determining unit 323, where the gray-scale value obtaining unit 321 is configured to obtain initial gray-scale values at different positions on the transferred image and corresponding target gray-scale values at different positions on the preset image; the gray scale difference obtaining unit 322 is configured to obtain a difference between an initial gray scale value and a target gray scale value at the same position; the determining unit 323 is configured to determine that the photomask has a defect if the absolute value of the difference is greater than or equal to a preset threshold. The target image transferred to the wafer through the photomask is abnormal due to the defect of the photomask, and the defect of the photomask is judged if the absolute value of the difference is greater than or equal to the preset threshold value by acquiring the difference between the initial gray-scale value and the target gray-scale value at the same position, so that the efficiency and the precision of defect detection of the photomask are effectively improved.

By way of example, continuing to refer to fig. 9, the determining unit 323 is further configured to: and if the difference value is within the preset precision range, judging that the photomask meets the requirement. If the precision of the target image transferred to the wafer through the photomask is within the preset precision range and meets the precision requirement of the target image transferred by the photomask, the photomask is judged to meet the detection requirement, and the precision of defect detection on the photomask is improved.

Referring to FIG. 10, in some embodiments of the present disclosure, a mask inspection apparatus 300 is provided for inspecting a mask for defects in any of the embodiments of the present disclosure; the device comprises a projection module 41 and a judgment module 42, wherein the projection module 41 is used for projecting a target light beam to a target area of a photomask, and a light calibration mark is arranged in the target area; the judging module 42 is configured to obtain a real-time calibration parameter of the target area for the target light beam, compare the real-time calibration parameter with a preset standard parameter in a standard database, and judge whether the photomask has a defect according to a comparison result. Because the target area comprises the first mark graph, the second mark graph and the third mark graph which are made of three different materials, the time spent on searching the three materials is effectively shortened, and the efficiency and the precision of defect detection of the photomask are improved.

The embodiments of the present disclosure also provide a computer device, which includes a memory and a processor, where the memory stores a computer program, and the processor implements the steps of the method according to any one of the above embodiments when executing the computer program.

The disclosed embodiments also provide a computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, implements the steps of the method according to any one of the above embodiments.

In the photomask detection method, the photomask detection device, the photomask detection equipment and the photomask detection medium in the embodiment, materials corresponding to three different materials, namely the first material, the second material and the third material, can be found on one optical calibration mark of the photomask body, and compared with the traditional photomask detection method which needs to search the materials corresponding to the three materials outside a target photomask detection area, the detection method has the advantages that the detection target is stronger and the detection efficiency is higher; because the adverse effect that the areas outside the target photomask detection area possibly interfere the detection light is avoided, the precision of photomask detection is effectively improved. Because the target area comprises the first mark graph, the second mark graph and the third mark graph of three different materials, the time spent on searching the three materials is effectively shortened.

It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware instructions of a computer program, which can be stored in a non-volatile computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. Any reference to memory, storage, database or other medium used in embodiments provided by the present disclosure may include at least one of non-volatile and volatile memory. Non-volatile Memory may include Read-Only Memory (ROM), magnetic tape, floppy disk, flash Memory, optical storage, or the like. Volatile Memory can include Random Access Memory (RAM) or external cache Memory. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM), for example.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features of the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present disclosure, and the description thereof is more specific and detailed, but not construed as limiting the claims. 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 (16)

1. A photomask is characterized by comprising a photomask body and a light alignment mark arranged on the photomask body;

the photomask body comprises a substrate made of a first material, a first pattern layer made of a second material and a second pattern layer made of a third material, which are sequentially overlapped along a first direction, wherein the first pattern layer and the second pattern layer are used for jointly limiting a transfer pattern of the photomask;

the light calibration mark comprises a first mark pattern made of a first material, a second mark pattern made of a second material and a third mark pattern made of a third material which are sequentially arranged along a second direction;

wherein the first direction is perpendicular to the second direction.

2. The mask of claim 1, wherein the first mark pattern is located on a same layer as the substrate, the second mark pattern is located on a same layer as the first pattern layer, and the third mark pattern is located on a same layer as the second pattern layer.

3. The mask of claim 1, wherein at least one of the first mark pattern, the second mark pattern, and the third mark pattern has a rectangular orthographic projection on the surface of the substrate.

4. The mask of claim 3, wherein the rectangle has a length or width in the range of 480nm-520 nm.

5. The mask of claim 3, wherein the orthographic projection of the first mark pattern on the surface of the substrate, the orthographic projection of the second mark pattern on the surface of the substrate and the orthographic projection of the third mark pattern on the surface of the substrate are the same in size.

6. The mask of claim 5, wherein an orthogonal projection of the first mark pattern on the surface of the substrate, an orthogonal projection of the second mark pattern on the surface of the substrate, and an orthogonal projection of the third mark pattern on the surface of the substrate are all squares.

7. The reticle of any one of claims 1-6 wherein the light alignment marks are located within a scribe lane area of the reticle body.

8. The optical mask according to any one of claims 1-6, wherein:

the first material, the second material and the third material are different and are selected from one of quartz, molybdenum silicide and chromium alloy.

9. A method for inspecting a photomask, comprising inspecting the photomask of any one of claims 1 to 8 for the presence of a defect; the method comprises the following steps:

projecting a target light beam to a target area of the reticle, the target area having the light alignment mark disposed therein;

acquiring real-time calibration parameters of the target area to the target light beam;

and comparing the real-time calibration parameters with corresponding preset standard parameters in a standard database, and judging whether the photomask has defects according to the comparison result.

10. The method of claim 9, wherein the target beam comprises a first beam of light at a first wavelength, a second beam of light at a second wavelength, and a third beam of light at a third wavelength; the projecting a target beam to a target area of the reticle includes:

projecting a first light beam at a first wavelength onto a first pattern of marks within the target area;

projecting a second light beam at a second wavelength onto a second pattern of marks within the target area;

a third beam of light of a third wavelength is projected onto a third pattern of marks in the target area.

11. The method of claim 10, wherein the real-time calibration parameters comprise a first calibration parameter, a second calibration parameter, and a third calibration parameter; the acquiring real-time calibration parameters of the target area to the target beam comprises:

acquiring a first calibration parameter of the first mark pattern to the first light beam;

acquiring a second calibration parameter of the second mark pattern to the second light beam;

and acquiring a third calibration parameter of the third mark pattern to the third light beam.

12. The method according to claim 11, wherein the preset standard parameters comprise a first standard parameter, a second standard parameter and a third standard parameter; the comparing the real-time calibration parameter with the corresponding preset standard parameter and judging whether the photomask has defects according to the comparison result comprises the following steps:

if the first calibration parameter is larger than the first standard parameter, judging that the photomask has a first defect;

if the second calibration parameter is larger than the second standard parameter, determining that the photomask has a second defect;

and if the third calibration parameter is larger than the third standard parameter, judging that the photomask has a third defect.

13. The method according to any one of claims 9-12, further comprising:

and projecting light beams with different wavelengths onto different mark patterns in the target area, respectively measuring and calculating reflectivity and transmissivity data, and storing the data into the standard database.

14. A reticle inspection apparatus for inspecting a reticle for the presence of a defect in the reticle of any one of claims 1 to 8; the device comprises:

the projection module is used for projecting the target light beam to a target area of the photomask, and the light calibration mark is arranged in the target area;

and the judging module is used for acquiring the real-time calibration parameters of the target area to the target light beam, comparing the real-time calibration parameters with corresponding preset standard parameters in a standard database, and judging whether the photomask has defects according to the comparison result.

15. A reticle inspection device comprising a memory and a processor, the memory storing a computer program, wherein the processor when executing the computer program realizes the steps of the method of any one of claims 9 to 13.

16. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method of any one of claims 9 to 13.

Images