Mask, mask detection device, mask existence and pose detection system and detection method

Abstract

The invention relates to the technical field of semiconductors, and provides a mask plate, a mask plate detection device, a mask plate existence and pose detection system and a mask plate existence and pose detection method. The plate body is provided with a non-light-transmitting area and a light-transmitting area; at least two detection positions, namely a first detection position and a second detection position, are arranged on the plate body; the detection position is located in the non-light-transmitting area; when the plate body placement posture is a standard posture, the first detection position refers to the position where the fixed part is located as a first reference position, the second detection position refers to the position where the fixed part is located as a second reference position, and when the plate body rotates by any angle around the central axis perpendicular to the plate body with the standard posture as the initial posture, the first reference position is located. At least one of the first reference position and the second reference position does not coincide with the light-transmitting area of the plate body. According to the invention, the detection position is arranged in the non-light-transmitting area on the mask plate and is matched with the optical sensor to identify whether the mask exists and whether the pose of the mask plate is correct.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly relates to a mask, a mask detection device, a mask presence and pose detection system, and a detection method. Background Art

[0002] A mask is a core component of the lithography process. The mask is usually placed in a mask library. During the lithography process, the mask is taken out from the mask library by a conveying device and conveyed to a specified position.

[0003] In an existing mask library, an optical sensor is usually provided. The optical sensor faces the mask directly to detect whether there is a mask in the mask library. The optical sensor generally determines whether there is a mask in the mask library by detecting the distance from the mask or by the intensity of the reflected light.

[0004] An existing mask usually has a light-transmitting area and a non-light-transmitting area. Therefore, when the mask is placed in the mask library and its placement pose is incorrect, for example, when the mask rotates a certain angle along the central axis perpendicular to it, the position where the optical sensor faces the mask changes at this time. The optical sensor may face the light-transmitting area of the mask or may face the non-light-transmitting area of the mask. Therefore, when the pose of the mask has a deviation, the above detection method may produce a misjudgment. Therefore, it is impossible to correctly identify whether there is a mask in the mask library, so abnormal situations such as plate collision may occur. And the above detection device cannot detect whether the pose of the mask has a deviation either.

[0005] On this basis, a mask, a mask detection device, a mask presence and pose detection system, and a detection method are proposed to correctly identify whether there is a mask in the mask library and to identify whether the pose of the mask is correct. Summary of the Invention

[0006] The invention provides a mask, a mask detection device, a mask presence and pose detection system, and a detection method to correctly identify whether there is a mask in the mask library and to identify whether the pose of the mask is correct.

[0007] The mask includes: a plate body;

[0008] The plate body has a non-light-transmitting area and a light-transmitting area;

[0009] At least two detection positions are provided on the plate body, which are a first detection position and a second detection position respectively;

[0010] The detection positions are located in the non-light-transmitting area;

[0011] The positions of the first detection position and the second detection position on the plate body are configured such that when the placement posture of the plate body is the standard posture, the first detection position refers to the position of the stationary member as the first reference position, and the second detection position refers to the position of the stationary member as the second reference position. When the plate body takes the standard posture as the initial posture and rotates by any angle around the central axis perpendicular to the plate body, at least one of the first reference position and the second reference position does not coincide with the light-transmitting area of the plate body.

[0012] Optionally, the plate body is square;

[0013] The positions of the first detection position and the second detection position on the plate body are further configured such that when the plate body takes the standard posture as the initial posture and rotates by 90°, 180°, and 270° respectively around the central axis perpendicular to the plate body, at least one of the first reference position and the second reference position does not coincide with the light-transmitting area of the plate body.

[0014] Optionally, an information recognition position is provided on the plate body;

[0015] The information recognition position is located in the light-transmitting area or the non-light-transmitting area;

[0016] When the information recognition position is located in the light-transmitting area and the plate body is square, the information recognition position is not set at the middle position of the plate body along the direction of one of its side lengths.

[0017] The present invention also provides a mask detection device, including an optical sensor and the mask described above;

[0018] The optical sensor at least includes a first optical sensor and a second optical sensor; the heads of the first optical sensor and the second optical sensor have an optical emission part and an optical reception part;

[0019] When the plate body is in the standard posture, the head of the first optical sensor points to the first detection position, and the head of the second optical sensor points to the second detection position.

[0020] Optionally, the mask detection device further includes a mask storage unit;

[0021] The mask storage unit has an accommodation space for placing the mask;

[0022] When the first optical sensor and the second optical sensor are arranged on the mask storage unit and the mask is placed in the accommodation space and in the standard posture, the head of the first optical sensor points to the first detection position, and the head of the second optical sensor points to the second detection position.

[0023] Optionally, the mask storage unit includes a library, in which a cassette is placed. The first optical sensor and the second optical sensor are arranged in the library. The cassette is used to place the mask. At least one side of the cassette is a light-transmitting side. The heads of the first optical sensor and the second optical sensor point to the mask in the cassette through the light-transmitting side of the cassette.

[0024] The present invention also provides a mask presence and pose detection system, including a conveying device, an information reading device, and the above-mentioned mask detection device;

[0025] An information identification position is arranged on the plate body;

[0026] The information reading device is used to read the information of the information identification position;

[0027] The conveying device is used to convey the mask in the mask storage unit to a specified position of the information reading device;

[0028] The position of the information reading device is configured such that when the mask is in a standard pose in the mask library and the mask is conveyed to the specified position, the information reading end of the information reading device points to the information identification position.

[0029] The present invention also provides a mask pose detection method, including the following steps:

[0030] S1: Detect the mask in the mask storage unit through the first optical sensor and the second optical sensor installed on the mask storage unit. If the mask information fed back by the first optical sensor and the second optical sensor does not show any abnormality, execute step S2; if at least one of the mask information fed back by the first optical sensor and the second optical sensor shows an abnormality, the mask pose is incorrect;

[0031] S2: Convey the mask to a specified position of the information reading device through the conveying device for information reading. If the information reading is correct, the mask pose is correct; if the information reading is incorrect, the mask pose is incorrect.

[0032] Optionally, in step S1, the following method is used to judge whether the displays of the first optical sensor and the second optical sensor are abnormal:

[0033] The first optical sensor and the second optical sensor emit laser light and detect the laser reflectivity. If the laser reflectivity is within the threshold range, the display result is considered normal; if the laser reflectivity exceeds the threshold range, the display result is considered abnormal.

[0034] Optionally, in step S2, if the mask pose is correct, execute step S3;

[0035] S3: The conveying device transports the reticle from the inner cassette or buffer table to the pre-alignment station and then to the mask table;

[0036] Or, the conveying device transports the reticle from the inner cassette or buffer table to the mask table.

[0037] The reticle presence and pose detection system is configured such that, in the present invention, a first detection position and a second detection position are set in the non-translucent area of the reticle, and the positions of the first detection position and the second detection position are defined. The first optical sensor and the second optical sensor respectively point to the first detection position and the second detection position when the reticle is in the standard pose, so that when the actual placement pose of the reticle deviates from the standard pose, it can be effectively identified by the first optical sensor and the second optical sensor. On the one hand, the reticle cooperates with the first optical sensor and the second optical sensor to correctly identify whether there is a reticle in the reticle storage unit, and the misjudgment phenomenon of whether there is a reticle can be completely eliminated. On the other hand, the reticle cooperates with the first optical sensor and the second optical sensor to also identify whether the pose of the reticle placed in the reticle storage unit is incorrect, which is beneficial to avoiding abnormal situations such as plate collision, avoiding losses caused by misoperation of operators, and at the same time avoiding accidental misdetection situations and reducing downtime losses. Brief Description of the Drawings

[0038] Figure 1 It is a schematic structural diagram of the reticle presence and pose detection system according to the first embodiment of the present invention;

[0039] Figure 2 It is a schematic structural diagram of the reticle detection device according to the first embodiment of the present invention;

[0040] Figure 3 It is a schematic structural diagram of the reticle according to the first embodiment of the present invention;

[0041] Figure 4a It is a schematic diagram when the reticle is in the standard pose;

[0042] Figure 4b It is a schematic diagram of the state when the reticle rotates 90° clockwise in the standard pose;

[0043] Figure 4c It is a schematic diagram of the state when the reticle rotates 180° clockwise in the standard pose;

[0044] Figure 4d It is a schematic diagram of the state when the reticle rotates 270° clockwise in the standard pose;

[0045] Figure 5a It is a schematic diagram when the reticle is in the inverted pose;

[0046] Figure 5b Schematic diagram of the state where the mask plate rotates 90° clockwise in Figure 5a ;

[0047] Figure 5c Schematic diagram of the state where the mask plate rotates 180° clockwise in Figure 5a ;

[0048] Figure 5d Schematic diagram of the state where the mask plate rotates 270° clockwise in Figure 5a ;

[0049] Figure 6 Schematic diagram of the structure of the mask plate according to the second embodiment of the present invention.

[0050] Among them, the reference numerals are as follows:

[0051] 100 - conveying device; 200 - information reading device; 300 - mask plate detection device; 400 - workbench; 500 - mask table;

[0052] 10 - plate body; 11 - first detection position; 12 - second detection position; 13 - information recognition position; 14 - pre - alignment identification area; 15 - manual identification code area; 16 - exposure pattern area; 17 - protection frame; 18 - protection frame bonding area; 19 - light - transmitting function area;

[0053] 20 - optical sensor; 21 - first optical sensor; 22 - second optical sensor;

[0054] 30 - mask plate storage unit; 31 - accommodation space; 301 - library;

[0055] 40 - cassette.

[0056] As used in the invention, the singular forms "a", "an" and "the" include plural referents, the term "or" is generally used in the sense of including "and / or", the term "several" is generally used in the sense of including "at least one", the term "at least two" is generally used in the sense of including "two or more", in addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", "third" may explicitly or implicitly include one or at least two of such features. In addition, as used in the invention, "mounted", "connected", "coupled", an element "disposed" on another element shall be understood in a broad sense, generally only indicating that there is a connection, coupling, cooperation or transmission relationship between the two elements, and the two elements may be directly or indirectly connected, coupled, cooperated or transmitted through an intermediate element, and cannot be construed as indicating or implying the spatial position relationship between the two elements, that is, an element may be in any orientation such as inside, outside, above, below or on one side of another element, unless the content clearly indicates otherwise. For those of ordinary skill in the art, the specific meanings of the above terms in the invention can be understood according to specific circumstances. In addition, directional terms such as above, below, up, down, upward, downward, left, right, etc. are used with respect to the exemplary embodiments as shown in the figures, with the upward or upper direction facing the top of the corresponding figure and the downward or lower direction facing the bottom of the corresponding figure.

[0057] The reticle is a core component of the lithography process. The reticle is usually placed in a reticle library, and during the lithography process, the reticle is taken out from the reticle library by a conveying device.

[0058] An optical sensor is usually provided in the existing reticle library. The optical sensor faces the reticle directly to detect whether there is a reticle in the reticle library. This optical sensor generally determines whether there is a reticle in the reticle library by detecting the distance from the reticle or by the intensity of the reflected light.

[0059] The existing reticle usually has a light-transmitting area and a non-light-transmitting area. Therefore, when the reticle is placed in the reticle library and its placement pose is incorrect, for example, when the reticle rotates by a certain angle along the central axis perpendicular to it, at this time, the position where the optical sensor faces the reticle changes, and the optical sensor may face the light-transmitting area of the reticle or may face the non-light-transmitting area of the reticle. Therefore, when the pose of the reticle has a deviation, the above detection method may produce a misjudgment, so it is impossible to correctly identify whether there is a reticle in the reticle library, and thus abnormal situations such as reticle collision may occur. And the above detection device cannot detect whether the pose of the reticle has a deviation either.

[0060] On this basis, a mask, a mask detection device, a mask presence and pose detection system, and a detection method are proposed to accurately identify whether there is a mask in the mask library and whether the pose of the mask is correct.

[0061] Embodiment 1:

[0062] In this embodiment, a mask presence and pose detection system is proposed;

[0063] As Figure 1 shown, the mask presence and pose detection system includes a conveying device 100, an information reading device 200, and a mask detection device 300.

[0064] Among them, the conveying device 100 and the information reading device 200 are arranged on a workbench 400, and a mask table 500 is also arranged on the workbench 400 for subsequent lithography processes.

[0065] Corresponding equipment can also be adaptively arranged on the workbench 400 based on subsequent process requirements.

[0066] The conveying device 100 can adopt an existing manipulator, for example, an existing mask fork structure. This conveying device is prior art and will not be elaborated here.

[0067] The information reading device 200 is set based on the type of information read. For example, when the information read is a barcode, the information reading device 200 is a barcode reader; when the information read is a QR code, the information reading device 200 is a QR code reader. Of course, the information reading device 200 can also be an image recognition device for identifying graphic information.

[0068] Please refer to Figure 2 and Figure 3 shown, the mask detection device 300 includes a mask, an optical sensor 20, and a mask storage unit 30;

[0069] Among them, the mask storage unit 30 has a receiving space 31, and the receiving space 31 is used to place the mask.

[0070] Specifically, the mask storage unit 30 includes a mask library 301. A mask box 40 is placed in the mask library 301. The mask box 40 has a cuboid structure and is slidably arranged in the mask library 301. The mask box 40 and the mask library 301 form a drawer structure, and the top of the mask box 40 is made of a light-transmitting material.

[0071] The structure of the plate library 301 is mainly composed of a plate library bottom plate, a right guide bracket, a plate library cover plate, a left guide bracket, etc. The plate box 40 is mainly composed of a plate box body, a plate box cover, a plate box slide rail, a mask plate support seat and a plate box bottom plate, etc. The plate box cover is a foldable structure, which is a light-transmitting material as the top of the plate box 40 and can transmit light well; the plate box bottom plate is a natural metal material as the bottom of the top of the plate box 40.

[0072] The plate box 40 can be drawn out of the plate library 301, and then the light-transmissive plate box cover can be opened to take in and put in the mask. In one embodiment, the mask is taken in and put in by the conveying device 100.

[0073] Please continue to refer to Figure 2 As shown, the optical sensor 20 at least includes a first optical sensor 21 and a second optical sensor 22; the heads of the first optical sensor 21 and the second optical sensor 22 have an optical transmitting part and an optical receiving part.

[0074] The first optical sensor 21 and the second optical sensor 22 are disposed on the top inner side of the plate library 301 , and the first optical sensor 21 and the second optical sensor 22 are directed toward the inside of the plate box 40 through the light-transmissive plate box cover of the plate box 40 .

[0075] In other alternative embodiments, the bottom of the plate box 40 may be made of a light-transmitting material, in which case the first optical sensor 21 and the second optical sensor 22 are disposed on the bottom inner side of the plate library 301 , and point toward the interior of the plate box 40 through the light-transmitting bottom of the plate box 201 .

[0076] Figure 3 The corresponding version body 10 is in a state when the posture is correct, and the version body 10 takes the correct posture as the standard posture.

[0077] The mask storage unit 30 is generally movable. When the mask needs to be loaded, the mask is placed in the mask storage unit 30. The mask storage unit 30 is moved to a specified position near the workbench 400 and faces the workbench 400 in a set posture. Therefore, the posture of the mask placed in the mask storage unit 30 is determined relative to the workbench 400. Then, the mask in the mask storage unit 30 can be taken out by the conveying device and conveyed to the specified position.

[0078] When the mask is placed in the accommodating space 31 and is in a standard posture, the head of the first optical sensor 21 passes through the light-transmitting upper cover of the plate box 40 to point to the first detection position 11, and the head of the second optical sensor 22 passes through the light-transmitting upper cover of the plate box 40 to point to the second detection position 12.

[0079] The main functions of the optical sensor 20 are to detect whether the mask is placed correctly in the cassette 40 and whether the mask exists. When the posture is correct, the mask can continue to flow to the next process through the conveying device 100. When the posture is incorrect or there is no mask, the conveying device 100 can report an error in time and stop the operation to avoid the risks of plate collision and plate dropping.

[0080] The optical sensor 20 uses, for example, an infrared sensor, a laser sensor, or other types of sensors, such as an industrial camera. The optical sensor 20 can determine whether the laser emitted by the optical sensor 20 is directed to the non-transmissive area of the mask or to the bottom of the cassette by detecting the intensity of the reflected light.

[0081] When the laser of the optical sensor 20 is directed to the non-transmissive area of the mask and to the bottom of the cassette, the reflectivities are different, and the pointing position of the laser can be determined by the reflectivity.

[0082] For example, when the laser of the optical sensor 20 is directed to the non-transmissive area of the mask, the reflectivity is low, and when it is directed to the bottom of the cassette, the reflectivity is high; or when the laser of the optical sensor 20 is directed to the non-transmissive area of the mask, the reflectivity is high, and when it is directed to the bottom of the cassette, the reflectivity is low. The detection logic is the same in either case.

[0083] In this embodiment, it is described by taking the example that when the laser of the optical sensor 20 is directed to the non-transmissive area of the mask, the reflectivity is low, and when it is directed to the bottom of the cassette, the reflectivity is high.

[0084] In this embodiment, the bottom of the cassette 40 is the natural color of the metal, with a high light reflectivity. When the laser emitted by the optical sensor 20 is directed to the bottom of the cassette, the intensity of the reflected light detected by the optical sensor 20 is strong, so the light reflectivity is higher than the reflection threshold.

[0085] In this embodiment, the non-transmissive area on the mask is a chromium plating layer, which has a darker color and absorbs most of the laser. Therefore, when the laser emitted by the optical sensor 20 is directed to the non-transmissive area of the mask, the intensity of the reflected light detected by the optical sensor 20 is weak, so the light reflectivity is lower than the reflection threshold.

[0086] When there is no mask placed in the cassette 40, the laser emitted by the optical sensor 20 directly reaches the bottom of the cassette 40, and the light reflectivity is higher than the reflection threshold.

[0087] When the placement posture of the mask in the cassette 40 is incorrect and the optical sensor 20 is facing the transmissive area of the mask, the detected light reflectivity is also higher than the reflection threshold.

[0088] When the placement posture of the reticle in the cassette 40 is incorrect and the optical sensor 20 is facing the non-transmissive area of the reticle, the laser emitted by the optical sensor 20 reaches the reticle. Since the non-transmissive area of the reticle is a chromium plating layer, most of the light beam emitted by the optical sensor 20 will be absorbed by the black chromium layer. At this time, the intensity of the reflected light reflected back to the optical sensor 20 is weak, and the detected light reflectivity is lower than the reflection threshold. At this time, it can be known that there is a reticle in the cassette 40.

[0089] When the placement posture of the reticle in the cassette 40 is the standard posture and the optical sensor 20 is facing the non-transmissive area of the reticle, the detected light reflectivity is lower than the reflection threshold.

[0090] Therefore, through the cooperation of the first optical sensor 21 and the second optical sensor 22, it is possible to identify whether there is a reticle in the cassette 40 and whether the placement posture of the reticle is correct. The specific detection process will be described in detail in the following content.

[0091] Please continue to refer to Figure 3 As shown, the reticle includes: a reticle body 10;

[0092] The reticle body 10 has a non-transmissive area and a transmissive area; the reticle body 10 is of a plate structure, which is generally made of transmissive glass material. Generally, a layer of metal chromium and photosensitive glue is inlaid on the reticle body 10. The circuit pattern is exposed on the photosensitive glue according to the electronic device laser cutting equipment. The metal chromium layer in the exposed area will be removed by the developer, and then a circuit pattern will be generated on the metal chromium, becoming a photomask similar to the exposed film. Subsequently, projection positioning is carried out, and the projected circuit is etched by a lithography machine.

[0093] The area removed by the developer is the transmissive area on the reticle body 10, and the area with the chromium plating layer is the non-transmissive area on the reticle body 10. As Figure 3 shown, the hatched areas in the figure are all chromium-plated non-transmissive areas, and the remaining areas are transmissive areas.

[0094] As Figure 3 shown, two detection positions are set on the reticle body 10, namely a first detection position 11 and a second detection position 12; the first detection position 11 and the second detection position 12 are set based on the positions of the first optical sensor 21 and the second optical sensor 22. When the reticle body 10 is in the standard posture, the position where the first optical sensor 21 faces the upper surface of the reticle body 10 is the first detection position 11, and the position where the second optical sensor 22 faces the upper surface of the reticle body 10 is the second detection position 12.

[0095] The detection positions are located in the non-transmissive area;

[0096] Please refer to Figure 3 shown, the reticle body 10 is also provided with other functional areas;

[0097] For example, based on the usage requirements, an information recognition bit 13 is also provided in this embodiment;

[0098] In this embodiment, the information recognition bit 13 is provided with a bar code, which is attached to the light-transmitting area, and the information reading device 200 is a bar code reader. In one embodiment, the information recognition bit 13 is located at Figure 3 a position slightly above the middle of the right side of the middle plate body 10. The information recognition bit 13 is not provided at the middle position of the plate body 10 along the direction of one of its side lengths. It should be noted that if the information recognition bit 13 is located at the middle of one edge of the plate body 10 and is a symmetric figure along the direction of that edge, it is also within the scope of the above-mentioned middle position. Through the above limitation, when the plate body 10 is reversed, the actual position of its information recognition bit 13 has a dislocation relationship with the corresponding position of the plate body 10 in the standard pose. Through this setting, the requirement of identifying the front and back of the plate body 10 can be met only by one information recognition bit 13, which helps to save valuable space on the mask plate.

[0099] Of course, the information recognition bit 13 can also be located in the non-light-transmitting area; when the plate body 10 is in the standard posture, its information recognition bit 13 is exposed upward and can be recognized. When the plate body 10 is reversed, the information recognition bit 13 faces downward and is blocked by the non-light-transmitting area, and at this time it cannot be recognized, so as to judge whether the plate body 10 is reversed.

[0100] Please continue to refer to Figure 3 As shown, the functional area further includes a pre-alignment identification area 14. The pre-alignment identification area 14 is a light-transmitting "cross" shaped marking area, and there are two alignment identification areas 14, which are respectively located at the positions of two adjacent corners of the plate body 10. The two alignment identification areas 14 can mark one side of the plate body 10. The orientation of the standard posture of the mask plate is that the edge corresponding to the pre-alignment "cross" shaped identification faces the inside of the mask storage unit 30 and the chrome-plated surface faces downward; when the mask plate is placed in the mask storage unit 30 and the posture is correct, the side of the plate body 10 marked by the alignment identification area 14 faces the inside of the mask storage unit 30.

[0101] In other alternative embodiments, the pre-alignment identification area 14 can also use other structures, such as using color identification or a certain entity structure on the plate body 10 as a mark. The specific structure and setting position of the pre-alignment identification area 14 can be adjusted adaptively based on actual requirements.

[0102] Please continue to refer to Figure 3 As shown, the functional area further includes an artificial identification code area 15 and an exposure pattern area 16. The artificial identification code area 15 records the information of the mask plate and is used for artificial identification or extraction of the corresponding mask plate information. The exposure pattern area 16 has a circuit pattern for lithography.

[0103] The functional area also includes a plurality of light-transmitting functional areas 19, and their functions and positions are determined based on actual requirements.

[0104] In addition, the mask also includes a protection frame 17. There is a protection frame bonding area 18 on the plate body 10, and the protection frame 17 is pasted on the protection frame bonding area 18 to protect the plate body 10.

[0105] Please continue to refer to Figure 3 as shown in Figure 3 The first optical sensor 21 and the second optical sensor 22 in are only used to reveal the relative positional relationship between the sensor and the first detection position 11 and the second detection position 12. Figure 3 The first optical sensor 21 and the second optical sensor 22 in are not features on the mask.

[0106] When the mask is placed in the cassette 40 in a standard posture, the center of the light spot of the first optical sensor 21 is directly opposite to the first detection position 11, and the center of the light spot of the second optical sensor 22 is directly opposite to the second detection position 12.

[0107] The positions of the first detection position 11 and the second detection position 12 on the plate body 10 are configured as follows: when the plate body 10 is placed in a standard posture, the first detection position 11 is the first reference position with reference to the position of the fixed part, and the second detection position 12 is the second reference position with reference to the position of the fixed part. When the plate body 10 takes the standard posture as the initial position and the plate body 10 rotates by any angle around the central axis perpendicular to the plate body 10, at least one of the first reference position and the second reference position does not coincide with the light-transmitting area of the plate body 10.

[0108] It should be further emphasized that the first detection position 11 and the second detection position 12 are positions on the plate body 10, and they will rotate with the rotation of the plate body 10; the first reference position and the second reference position are positions relative to the fixed part, such as the position relative to the workbench 400 or the position with reference to the foundation. Therefore, the first reference position and the second reference position do not change with the movement of the plate body 10.

[0109] The plate body 10 can be circular. Since the outer contour of the plate body 10 remains the same when it rotates by any angle, its placement posture is relatively difficult to identify. At this time, it is necessary to ensure that when the plate body 10 rotates by any angle around the central axis perpendicular to the plate body 10, at least one of the first reference position and the second reference position does not coincide with the light-transmitting area of the plate body 10. At this time, it is convenient to detect whether the position and posture of the circular plate body 10 are correct, and its detection logic is the same as the detection logic of the following square plate body. For the specific detection logic, please refer to the description of the following square plate body.

[0110] Existing masks are usually set as square plates. Therefore, in this embodiment, a square mask is taken as an example for description.

[0111] Figure 3 The corresponding plate body 10 is the posture when the posture is correct. The plate body 10 takes the correct posture as the standard posture. Before the reticle is transported to the workbench 400, the posture of the plate body 10 relative to the workbench 400 should be the standard posture. Therefore, when the conveying device 100 grabs the reticle, the posture of the reticle relative to the conveying device 100 remains correct to ensure that the posture of the reticle in the subsequent process always remains correct.

[0112] In this embodiment, the plate body 10 is square; the central axis perpendicular to the plate body 10 is the central axis of the inscribed circle of the plate body 10. When the plate body 10 is square, its placed posture is relatively easy to identify. When the plate body 10 is placed in the plate cassette, the internal space of the plate cassette is also roughly square. Since the plate body 10 cannot be placed in the plate cassette when it is slightly skewed, the placement direction of the plate body 10 is limited when it is placed in the plate cassette. When placed correctly, after the plate body 10 is placed in the plate cassette, there are only four pose situations: the standard pose, and rotating 90°, 180°, and 270° around the central axis perpendicular to the plate body 10 with the standard pose as the initial pose. The same is true for the reverse placement. Therefore, based on the actual placement situation of the square reticle, in this implementation, the reticle is not detected when it rotates at an arbitrary angle around the central axis perpendicular to the plate body 10, and only the above four poses need to be detected. Therefore, the positions of the first detection position 11 and the second detection position 12 on the plate body 10 in the present invention are further configured as: when the plate body 10 rotates 90°, 180°, and 270° around the central axis perpendicular to the plate body 10 with the standard pose as the initial pose, at least one of the first reference position and the second reference position does not coincide with the light-transmitting area of the plate body 10.

[0113] Please continue to refer to FIG. 3. In one embodiment, when the plate body 10 is in the standard pose, the first detection position 11 is located at the upper left position of the plate body 10, and the second detection position 12 is located at the lower left position of the plate body 10.

[0114] Please refer to FIGS. 4a to Figure 4d As shown, when the light reflectivity feedback by the first optical sensor 21 is higher than the reflection threshold, it means that the laser hits the bottom of the plate cassette 40. At this time, it is uncertain whether there is a reticle in the plate cassette 40. When the light reflectivity feedback by the first optical sensor 21 is lower than the reflection threshold, it means that the laser hits the reticle. At this time, it is determined that there is a reticle in the plate cassette 40.

[0115] When the light reflectivity feedback by the second optical sensor 22 is higher than the reflection threshold, it means that the laser hits the bottom of the plate cassette 40. At this time, it is uncertain whether there is a reticle in the plate cassette 40. When the light reflectivity feedback by the second optical sensor 22 is lower than the reflection threshold, it means that the laser hits the reticle. At this time, it is determined that there is a reticle in the plate cassette 40.

[0116] When the light reflectivity is higher than the reflection threshold, it is replaced by the feedback value 0, and when the light reflectivity is lower than the reflection threshold, it is replaced by the feedback value 1. Therefore, the combined feedback values of the first optical sensor 21 and the second optical sensor 22 have at most four combinations: (0, 0), (0, 1), (1, 0), and (1, 1). Among them, (0, 0) means there is no plate in the plate cassette, and (0, 1), (1, 0), and (1, 1) mean there is a plate in the plate cassette. The meanings of the four combinations will be further explained in detail below in conjunction with the accompanying drawings.

[0117] As Figure 4a shown, when the reticle is placed upright in the standard posture in the plate cassette 40, the first optical sensor 21 faces the first detection position 11, the second optical sensor 22 faces the second detection position 12, both the first optical sensor 21 and the second optical sensor 22 point to the non-transmissive area of the reticle, and the feedback value is (1, 1).

[0118] As Figure 4b shown, when the reticle rotates 90° clockwise based on the standard posture, the first optical sensor 21 points to the non-transmissive area of the reticle, the second optical sensor 22 points to the transmissive area of the reticle, and the feedback value is (1, 0). At this time, it can be known that there must be a reticle in the plate cassette 40, and the placement posture of the reticle is incorrect.

[0119] As Figure 4c shown, when the reticle rotates 180° clockwise based on the standard posture, the first optical sensor 21 points to the non-transmissive area of the reticle, the second optical sensor 22 points to the information recognition bit 13 of the reticle, and the feedback value is (1, 0) or (1, 1). At this time, it can be known that there must be a reticle in the plate cassette 40, and the placement posture of the reticle is uncertain.

[0120] As Figure 4d shown, when the reticle rotates 270° clockwise based on the standard posture, the first optical sensor 21 points to the non-transmissive area of the reticle, the second optical sensor 22 points to the transmissive area of the reticle, and the feedback value is (1, 0). At this time, it can be known that there must be a reticle in the plate cassette 40, and the placement posture of the reticle is incorrect.

[0121] Please refer to 5a to Figure 5d shown, which is a schematic diagram of the feedback value when the reticle is placed upside down.

[0122] As Figure 5a shown, it is the posture after the reticle is flipped from the standard posture ( Figure 4a the posture after the corresponding posture is flipped left and right). The first optical sensor 21 points to the non-transmissive area of the reticle, the second optical sensor 22 points to the non-transmissive area of the reticle, and the feedback value is (1, 1). At this time, it can be known that there must be a reticle in the plate cassette 40, and it is uncertain whether the placement posture of the reticle is accurate.

[0123] As Figure 5b shown, it is the posture of the reticle rotating 90° clockwise based on Figure 5a . The first optical sensor 21 points to the non-light-transmitting area of the reticle, and the second optical sensor 22 points to the light-transmitting area of the reticle. The feedback value is (1, 0). At this time, it can be known that there must be a reticle in the cassette 40, and the placement posture of the reticle is incorrect.

[0124] As Figure 5c shown, it is the posture of the reticle rotating 180° clockwise based on Figure 5a . The first optical sensor 21 points to the non-light-transmitting area of the reticle, and the second optical sensor 22 points to the manual identification code area 15 of the reticle. The feedback value is (1, 0) or (1, 1). At this time, it can be known that there must be a reticle in the cassette 40, and the placement posture of the reticle is uncertain.

[0125] As Figure 5d shown, it is the posture of the reticle rotating 270° clockwise based on Figure 5a . The first optical sensor 21 points to the non-light-transmitting area of the reticle, and the second optical sensor 22 points to the light-transmitting area of the reticle. The feedback value is (1, 0). At this time, it can be known that there must be a reticle in the cassette 40, and the placement posture of the reticle is incorrect.

[0126] Based on the settings of the positions of the first optical sensor 21 and the second optical sensor 22, the positions of the first reference position and the second reference position are determined. And when rotating around the central axis perpendicular to the plate body 10, at least one of the first reference position and the second reference position does not coincide with the light-transmitting area of the plate body 10. Therefore, when the feedback value (0, 0) appears, it can be excluded that it is caused by the incorrect posture of the reticle, indicating that there must be no reticle in the cassette 40. When the feedback values (0, 1) and (1, 0) appear, it means that there must be a reticle in the cassette 40, and the posture of the reticle is incorrect. When the feedback value (1, 1) appears, it means that there must be a reticle in the cassette 40, but it is uncertain whether the posture of the reticle is correct. At this time, the reticle may be in the standard posture or may be reversed.

[0127] When the feedback values are (0, 0), (0, 1), and (1, 0), it is judged that there is no reticle in the cassette 40 or there is a reticle and the position and posture are incorrect, and the machine stops for detection. At this time, the conveying device 100 does not perform the actions of taking out the reticle and conveying the reticle.

[0128] When the feedback value is (1, 1) and it is uncertain whether the posture of the reticle is correct, the conveying device 100 performs the actions of taking out the reticle and conveying the reticle, and conveys the reticle to the designated position of the information reading device 200;

[0129] The position of the information reading device 200 is configured such that when the mask is in a standard posture in the mask library 300 and the mask is transported to the designated position, the information reading end of the information reading device 200 points to the information identification bit 13. The designated position is, for example, an inner plate library or a buffer table.

[0130] That is, when the mask is in the Figure 4a shown posture, when the mask is transported to the designated position, the information reading end of the information reading device 200 points to the information identification bit 13.

[0131] When the mask is in the Figure 4a and Figure 5a postures, its feedback value is (1, 1). Since the information identification bit 13 is not set at the middle position of the plate body 10 along the direction of one of its side lengths, when the mask is in the Figure 5a posture, the information identification bit 13 changes and is not directly opposite to the information reading end of the information reading device 200. Therefore, at this time, the information reading end of the information reading device 200 cannot read the information of the information identification bit 13. At this time, it is considered that the mask posture is incorrect, and the machine stops for detection. When the information can be read, it is considered to be in the Figure 4a standard posture, and at this time, it is considered that the mask posture is correct and the subsequent process can be continued.

[0132] It should be further noted that in this embodiment, the information identification bit 13 is a bar code, and the manual identification code area 15 is provided with characters. Although both are set in the light-transmitting area of the mask, since the content of the information identification bit 13 and the manual identification code area 15 will affect light transmission, if the optical sensor 20 is directly opposite to the information identification bit 13 and the manual identification code area 15, the feedback value may be 0 or 1, and misjudgment may occur at this time. Therefore, when the mask rotates 90°, 180°, and 270° around its central axis, the information identification bit 13 and the manual identification code area 15 should be avoided from coinciding with the first reference position and the second reference position as much as possible. Because when the information identification bit 13 and the manual identification code area 15 coincide with the first reference position and the second reference position, their feedback value is uncertain and it is difficult to accurately identify the current posture.

[0133] Mask mask mask mask mask When the information identification bit 13 and the manual identification code area 15 coincide with the first reference position or the second reference position, that is, when the laser of the first optical sensor 21 and the second optical sensor 22 hits the information identification bit 13 or the manual identification code area 15, as Figure 4c and Figure 5c shown postures, when the information identification bit 13 and the manual identification code area 15 coincide with the first reference position and the second reference position, then Figure 4c the feedback to may be (1, 0) or (1, 1), similarlyFigure 5c The feedback value may be (1, 0) or (1, 1). When the feedback value is (1, 1), the conveying device 100 can normally pick up the mask plate and transfer the mask plate to the designated position of the information reading device 200. At this time, the information recognition bit 13 cannot be normally read because the placement orientation of the mask plate is incorrect. The conveying device 100 reports an error and stops working, ultimately achieving the purpose of preventing mistakes. The above entire process can realize the detection of whether there is a mask plate in the cassette, and can also realize the detection of whether the placement orientation of the mask plate is correct, achieving the purpose of preventing mistakes and preventing collision of the mask plate.

[0134] As described above, the coincidence of the information recognition bit 13 and the manual recognition code area 15 with the first reference position and the second reference position may increase the probability of the appearance of the (1, 1) feedback value. When the pose of the mask plate is incorrect, the probability of the conveying device 100 performing secondary recognition increases. Therefore, in this embodiment, it is further defined that when the plate body 10 rotates 90°, 180°, and 270° respectively around the central axis perpendicular to the plate body 10 with the standard pose as the initial pose, one of the first reference position and the second reference position coincides with the light-transmitting area, and one coincides with the non-light-transmitting area. Then it is ensured that when the mask plate is in the pose Figure 4a and Figure 5a shown, the feedback value of (1, 1) will appear, thereby eliminating the influence of the information recognition bit 13 and the manual recognition code area 15 on the feedback value.

[0135] In this embodiment, the first detection position 11 and the second detection position 12 are used in cooperation with the mask plate storage unit 30. In other alternative embodiments, they can also be used in cooperation with other structures according to the specific requirements of other application scenarios. For example, the first detection position 11 and the second detection position 12 are used in cooperation with the mask table of the lithography equipment.

[0136] In other alternative embodiments, more detection positions can be set, for example, three detection positions are set. Correspondingly, three optical sensors 20 are also set. By setting multiple detection positions, the vacant positions of the mask plate can be utilized more flexibly, facilitating the spatial layout of each detection position.

[0137] This embodiment also provides a method for detecting the pose of a mask plate, including the following steps:

[0138] S1: Detect the mask plate in the mask plate storage unit 30 through the first optical sensor 21 and the second optical sensor 22. If the mask plate information fed back by the first optical sensor 21 and the second optical sensor 22 does not show any abnormality, execute step S2; if there is at least one abnormal situation in the mask plate information fed back by the first optical sensor and the second optical sensor, the pose of the mask plate is incorrect.

[0139] In this embodiment, at the human-machine interface, the cassette 40 with the reticle is inserted into the reticle library 301, and then the reticle storage unit 30 is lifted to a high position by the vertical module, and the conveying device 100 can transfer and pick up the reticle. In this embodiment, the following method is used to determine whether the displays of the first optical sensor and the second optical sensor are abnormal:

[0140] The first optical sensor 21 and the second optical sensor 22 emit laser light and detect the laser reflectivity. If the laser reflectivity is within the threshold range, the display result is considered normal. If the laser reflectivity exceeds the threshold range, the display result is considered abnormal.

[0141] Combined with the above reticle detection device, when both the first optical sensor 21 and the second optical sensor 22 point to the non-transmissive area of the reticle, and the light reflectivities detected by the first optical sensor 21 and the second optical sensor 22 are both less than or equal to the reflection threshold, the display results of both are normal, that is, when the feedback value is (1, 1), step S2 is executed; when at least one of the light reflectivities detected by the first optical sensor 21 and the second optical sensor 22 points to the bottom of the reticle storage unit, at this time, at least one sensor detection value is higher than the reflection threshold, and the display result is abnormal, and its feedback value is 0, that is, when the feedback values of the two sensors are (0, 0), (1, 0), and (0, 1), the reticle pose is incorrect. Since at this time, the sensor may point to the bottom of the reticle storage unit through the transmissive area of the reticle, or there may be no reticle inside the reticle storage unit, and at this time, the sensor naturally points to the bottom of the reticle storage unit; therefore, the pose error here means that the reticle is not in the reticle storage unit 30 or the pose of the reticle placed in the reticle storage unit 30 is incorrect. At this time, the machine stops for detection, and the conveying device 100 does not perform the actions of picking up the reticle and transmitting the reticle.

[0142] The above judgment of abnormal and correct feedback results is based on the different reflectivities of the laser light irradiated on the reticle and the bottom of the cassette. In other alternative embodiments, distance detection or the recognition of other marks can be used to determine whether there is a reticle in the cassette. For example, when using distance detection, when the detected distance is the distance between the sensor and the reticle, the display result is considered normal, and when the detected distance is the distance between the sensor and the bottom of the cassette, the display result is considered abnormal.

[0143] S2: The conveying device 100 conveys the reticle to the designated position of the information reading device 200 for information reading. If the information reading is correct and the reticle pose is correct, step S3 is executed; if the information reading is incorrect, the reticle pose is incorrect. The information reading error here means that the information cannot be read or the read information is incorrect.

[0144] S3: When the reading is correct, the conveying device conveys the reticle from the inner cassette or buffer table to the pre-alignment station and then to the mask table; or, the conveying device conveys the reticle from the inner cassette or buffer table to the mask table.

[0145] Embodiment 2

[0146] The difference between this embodiment and Embodiment 1 lies in the different setting positions of the first detection position 11 and the second detection position 12.

[0147] As Figure 6 shown, the first detection position 11 is located at the middle position of the upper edge of the reticle in Figure 6 and the second detection position 12 is located at the middle and lower position on the left side of the reticle.

[0148] Correspondingly, the positions of the first optical sensor 21 and the second optical sensor 22 also change adaptively.

[0149] The specific positions of the first detection position 11 and the second detection position 12 can be adjusted according to the design of the light-transmitting area and non-light-transmitting area of the detected reticle. It is only necessary to adjust the structural parts for installing the detection sensors and the sensor installation method accordingly. The principle of adjustment is that the return value combination of the two first optical sensors 21 and the second optical sensor 22 meets the logic of presence and anti-fooling detection.

[0150] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0151] The above description is only a description of the preferred embodiments of the invention and does not limit the scope of the invention in any way. Any changes and modifications made by those of ordinary skill in the art according to the above disclosure fall within the protection scope of the claims.

Claims

1. A photomask, characterized in that, Comprising: A plate body; The plate body has a non-transmissive area and a transmissive area; At least two detection positions are provided on the plate body, namely a first detection position and a second detection position; The detection positions are located in the non-transmissive area; The positions of the first detection position and the second detection position on the plate body are configured such that when the placement posture of the plate body is the standard posture, the position of the first detection position with reference to the fixed part is the first reference position, and the position of the second detection position with reference to the fixed part is the second reference position. When the plate body rotates by any angle around the central axis perpendicular to the plate body with the standard posture as the initial posture, at least one of the first reference position and the second reference position does not coincide with the transmissive area of the plate body.

2. The reticle according to claim 1, wherein The plate body is square; The positions of the first detection position and the second detection position on the plate body are further configured such that when the plate body rotates 90°, 180°, and 270° respectively around the central axis perpendicular to the plate body with the standard posture as the initial posture, at least one of the first reference position and the second reference position does not coincide with the transmissive area of the plate body.

3. The reticle according to claim 1 or 2, characterized in that An information recognition position is provided on the plate body; The information recognition position is located in the transmissive area or the non-transmissive area; When the information recognition position is located in the transmissive area and the plate body is square, the information recognition position is not provided at the middle position along one side length direction of the plate body.

4. A mask detection device, characterized in that, Comprising an optical sensor and a mask plate as described in any one of claims 1 to 3; The optical sensor at least includes a first optical sensor and a second optical sensor; the heads of the first optical sensor and the second optical sensor have an optical emission part and an optical reception part; When the plate body is in the standard posture, the head of the first optical sensor points to the first detection position, and the head of the second optical sensor points to the second detection position.

5. The mask inspection device according to claim 4, wherein The mask plate detection device further includes a mask plate storage unit; The mask plate storage unit has an accommodation space for placing the mask plate; The first optical sensor and the second optical sensor are provided in the mask plate storage unit. When the mask plate is placed in the accommodation space and is in the standard posture, the head of the first optical sensor points to the first detection position, and the head of the second optical sensor points to the second detection position.

6. The mask inspection device according to claim 5, wherein The mask plate storage unit includes a plate library, and plate boxes are placed in the plate library. The first optical sensor and the second optical sensor are provided in the plate library. The plate boxes are used to place the mask plates. At least one side of the plate box is a transmissive side, and the heads of the first optical sensor and the second optical sensor pass through the transmissive side of the plate box and point to the mask plate in the plate box.

7. A mask presence and pose detection system, characterized in that, Comprising a conveying device, an information reading device, and a mask plate detection device as described in any one of claims 4 to 6; An information recognition position is provided on the plate body; The information reading device is used to read the information of the information recognition position; The conveying device is used to convey the mask plate in the mask plate storage unit to a specified position of the information reading device; The position of the information reading device is configured such that when the mask is in a standard posture in the mask library and the mask is transported to the designated position, the information reading end of the information reading device points to the information recognition bit.

8. A method for detecting the pose of a mask, characterized in that It includes the following steps: S1: Detect the mask in the mask storage unit through the first optical sensor and the second optical sensor installed on the mask storage unit. If the mask information fed back by the first optical sensor and the second optical sensor does not show any abnormality, execute step S2; if at least one of the mask information fed back by the first optical sensor and the second optical sensor shows an abnormality, the mask pose is incorrect. S2: Transport the mask to the designated position of the information reading device through the transport device for information reading. If the information reading is correct, the mask pose is correct; if the information reading is incorrect, the mask pose is incorrect.

9. The mask pose detection method according to claim 8, wherein In step S1, the following method is used to determine whether the displays of the first optical sensor and the second optical sensor are abnormal: The first optical sensor and the second optical sensor emit laser light and detect the laser reflectivity. If the laser reflectivity is within the threshold range, the display result is considered normal; if the laser reflectivity exceeds the threshold range, the display result is considered abnormal.

10. The mask pose detection method according to claim 8, wherein In step S2, if the mask pose is correct, execute step S3; S3: The transport device transports the mask from the inner mask library or the buffer table to the pre-alignment station and then to the mask table; Or, the transport device transports the mask from the inner mask library or the buffer table to the mask table.

Images