Photomask inspection device, and inspection method thereof

Abstract

Disclosed are a photomask inspection device, and an inspection method thereof. The photomask inspection device comprises: a stage unit for loading and moving a photomask; and, in front of the photomask, a gantry unit to which at least one of an inspection unit, a correction unit, and a cleaning unit is attached to inspect, correct, or clean the photomask.

Description

Photomask inspection device and inspection method thereof

[0001] An embodiment of the present invention relates to a photomask inspection device and an inspection method thereof, and more specifically, to a method and device for inspecting, correcting, and / or cleaning defects or foreign substances in a photomask.

[0002] A typical photomask manufacturing process consists of a front process that forms a pattern on a blank mask, a back-end process that inspects and removes (or cleans) defects and foreign substances, and a quality assurance process.

[0003] Figure 1 is a flowchart illustrating an example of a general photomask manufacturing process.

[0004] Referring to Fig. 1, first, a design GDS file is converted into a data format usable by an exposure device (S100). Using the converted data, an exposure process is performed on a blank mask (S105). A pattern is created on the blank mask through processes such as develop, etch, and strip (S110, S115, and S120). After the pattern is formed, the quality of the CD (critical dimension), registration, transmittance, and phase are measured (S125). The photomask is cleaned (S130), and the photomask on which the pattern is formed is inspected for defects (hard defects) or foreign substances (soft defects) (S135). If defects or foreign substances are found during the inspection (S140), a correction and cleaning process is performed to remove them (S145). After this, a second inspection process is performed to check for the presence of foreign substances, and if foreign substances are found during the second inspection process (S140), a third inspection process is performed after the second cleaning process. This inspection and correction process is repeated until all defects and foreign matter are eliminated. Once all defects and foreign matter have been removed, a pellicle is attached and inspected. If no foreign matter is found, the product is shipped (S150, S155). If foreign matter is found, the pellicle is removed and subsequent processes, starting with the cleaning process, are repeated.

[0005] Fig. 2 is a drawing showing an example of a part of a cleaning device for a general photomask.

[0006] Referring to Fig. 2, a photomask (220) for general semiconductor manufacturing or flat panel display manufacturing includes a first chamber (200) that uses an acid such as sulfuric acid to clean organic substances, and a second chamber (210) that subsequently uses alkaline cleaning to solve the haze problem caused by the use of acid. The photomask (220) needs to be moved between the first chamber and the second chamber. After going through the process of cleaning and drying using acid and alkali, foreign substances remaining on the photomask (220) have very strong adhesive strength and small sizes, so that they are strongly bonded to the surface and are difficult to remove with general air pressure.

[0007] In addition, in order to evenly spread the chemical substance over the entire surface of the photomask (220) during cleaning, and to wash the chemical substance with water and dry it, the photomask (220) is rotated at high speed through a spin chuck (230). There is a possibility that the photomask (220) may be contaminated with foreign substances and particles due to the rebound and air vortex in the chamber that occur when the photomask (220) is rotated for cleaning and / or drying. In addition, since chemicals are used, an external chamber (not shown) exists to block the inside of the first chamber (200) and the second chamber (210) from the outside, so the size of the cleaning device is also one of the largest devices in the photomask manufacturing line. Moreover, since the cleaning device has a structure that loads and transports the photomask (220) horizontally, it is easily exposed to particle contamination due to the spinning process, internal movement, and handling. Therefore, a process of inspecting for foreign substances, etc. is required again after the cleaning process, and if foreign substances are present, the cleaning process must be performed again. That is, the inspection process and cleaning process are repeated multiple times, making the photomask manufacturing process time-consuming.

[0008] Photomasks manufactured on a custom-built basis are critical to production lead times. The typical photomask manufacturing process, illustrated in Figures 1 and 2, involves inspection, defect correction, and cleaning to manage defects and foreign matter. The process (cleaning and correction) using a horizontal loading device and the movement of the photomask between each process device are prone to contamination, requiring inspection after cleaning. If foreign matter is detected, the cleaning and inspection process must be repeated multiple times, resulting in a significant time commitment for the entire manufacturing process.

[0009] The technical problem to be achieved by an embodiment of the present invention is to provide a photomask inspection device and an inspection method thereof, which can inspect for defects or foreign substances in a photomask and correct and / or clean them in one device, and can shorten the overall manufacturing process time by eliminating movement between devices for each process and preventing reverse contamination resulting from movement between devices.

[0010] In order to achieve the above technical task, an example of a photomask inspection device according to an embodiment of the present invention includes a stage unit for loading and moving a photomask; and a gantry unit to which at least one of an inspection unit, a correction unit, and a cleaning unit is attached for inspecting, correcting, or cleaning the photomask at the front side of the photomask.

[0011] In order to achieve the above technical task, an example of a photomask inspection method according to an embodiment of the present invention is a photomask inspection method performed by a photomask inspection device including a stage unit for moving a photomask, and a cabinet unit having an inspection unit, a correction unit, and a cleaning unit attached thereto, the method including: a step of identifying at least one inspection area in which a defect and / or a foreign substance of the photomask exists through movement control of the inspection unit and / or movement control of the photomask; and a step of correcting or cleaning the defect and / or the foreign substance of the inspection area by controlling the correction unit and / or the cleaning unit.

[0012] According to an embodiment of the present invention, since the photomask is loaded vertically to perform correction and / or cleaning, it is advantageous in preventing reverse contamination during the correction or cleaning process. In another embodiment, point cleaning is performed only on areas where foreign substances exist, rather than the entire photomask, and correction and / or cleaning can be performed in the same equipment, thereby reducing correction and / or cleaning waiting time, process time, and costs.

[0013] Figure 1 is a flow chart showing an example of a general photomask manufacturing process.

[0014] Figure 2 is a drawing showing an example of a general photomask cleaning process.

[0015] FIG. 3 is a drawing showing an example of a photomask inspection device according to an embodiment of the present invention;

[0016] FIG. 4 is a drawing showing another example of a photomask inspection device according to an embodiment of the present invention;

[0017] FIG. 5 is a drawing showing an example of a defect or foreign substance in a photomask inspected by a photomask inspection device according to an embodiment of the present invention.

[0018] FIG. 6 is a diagram illustrating an example configuration of a cleaning unit according to an embodiment of the present invention;

[0019] FIG. 7 is a diagram illustrating an example configuration of a modification unit according to an embodiment of the present invention;

[0020] FIG. 8 is a drawing showing an example of the arrangement structure of each module for inspection, modification, or cleaning according to an embodiment of the present invention;

[0021] FIG. 9 is a flowchart illustrating an example of an inspection method of a photomask inspection device according to an embodiment of the present invention.

[0022] FIG. 10 is a drawing showing another example of an inspection method of a photomask inspection device according to an embodiment of the present invention;

[0023] FIG. 11 is a drawing showing another embodiment of a photomask inspection device according to an embodiment of the present invention, and

[0024] FIG. 12 is a drawing illustrating another embodiment of a photomask inspection device according to an embodiment of the present invention.

[0025] Hereinafter, a photomask inspection device and an inspection method thereof according to an embodiment of the present invention will be described in detail with reference to the attached drawings.

[0026] FIG. 3 is a drawing illustrating an example of a photomask inspection device according to an embodiment of the present invention. The left figure in FIG. 3 is a front view of the photomask inspection device, and the right figure is a left side view of the photomask inspection device.

[0027] Referring to FIG. 3, the photomask inspection device includes a stage unit (310) and a gantry unit (320). The stage unit (310) loads a photomask (360) in a vertical direction and moves the photomask (360) in a left-right direction. For example, the stage unit (310) may include a grip unit (312) capable of vertically fixing the photomask (360) and rails for left-right movement of the grip unit (312) on the upper and lower horizontal axes, respectively. In addition, the stage unit (310) may be implemented in various structures capable of gripping the photomask (360) in a vertical direction and moving it in a left-right direction.

[0028] The gantry section (320) is positioned vertically in front of the stage section (310) and moves at least one of the inspection section (330), the correction section (340), and the cleaning section (350) in the vertical direction to inspect, correct, or clean the photomask (360). For convenience of explanation, the present embodiment presents a case in which the inspection section (330), the correction section (340), and the cleaning section (350) are all included.

[0029] In one embodiment, the gantry unit (320) may include a plurality of spaced apart gantries. For example, the gantry unit (320) may include a first gantry (322), a second gantry (324), and a third gantry (326). The first gantry (322) moves the inspection unit (330) up and down, the second gantry (324) moves the correction unit (340) up and down, and the third gantry (326) moves the cleaning unit (350) up and down. Although this embodiment illustrates an example in which the inspection unit (330), the correction unit (340), and the cleaning unit (350) are respectively sequentially located in the respective gantry units (322, 324, 326), this is only one example, and the positions of the gantries in which the inspection unit (330), the correction unit (340), and the cleaning unit (350) are located may be variously modified. For example, a correction unit (340) may be located on the first gantry (322), an inspection unit (330) may be located on the second gantry (324), and a cleaning unit (350) may be located on the third gantry (326).

[0030] The first gantry (322), the second gantry (324), and the third gantry (326) may have vertical rails for vertical movement of the inspection unit (330), the correction unit (340), and the cleaning unit (350). The inspection unit (330), the correction unit (340), and the cleaning unit (350) may move vertically along the rails of the first to third gantries (322, 324, 326), respectively. This embodiment illustrates an example in which the inspection unit (330), the correction unit (340), and the cleaning unit (350) are attached to independent first to third gantries (322, 324, 326) in order to reduce the influence between each process of inspection, correction, and cleaning, and to facilitate maintenance. However, this is only one example, and the structure of the gantry unit (320) may be modified in various ways depending on the embodiment.

[0031] In another embodiment, the gantry unit (320) may be implemented to include only some of the first to third gantries (322, 324, 326). For example, the gantry unit (320) may include only the first gantry (322), or only the first gantry (322) and the second gantry (324).

[0032] In another embodiment, the gantry unit (320) may attach two or more of the inspection unit (330), the correction unit (340), and the cleaning unit (350) to one gantry. For example, the gantry unit (320) may include only the first gantry (322), and three vertical rails may be positioned on the first gantry (320), and the inspection unit (330), the correction unit (340), and the cleaning unit (350) may be positioned on each rail, respectively. Alternatively, the gantry unit (320) may include first and second gantries (322, 324) (the third gantry is omitted), and the inspection unit (330) may be positioned on the first gantry (322), and the correction unit (340) and the cleaning unit (350) may be positioned on two rails, each of which may move independently. Alternatively, the second gantry (324) may include one rail, and the correction unit (340) and the cleaning unit (350) may be implemented as one module (unit) so that they can move up and down together in the second gantry (324). In addition, the number of gantries constituting the gantry section (320) and the structure of arranging the inspection unit (330), the correction unit (340), and the cleaning unit (350) on each gantry may be modified in various ways. An example of a photomask inspection device including one gantry is illustrated in FIG. 4.

[0033] The inspection unit (330) includes an optical module capable of inspecting the photomask (360) for defects and / or foreign substances. In one embodiment, the inspection unit (330) may be configured with an optical system including a light source and a lens unit capable of performing transmission inspection and reflection inspection. An example of the structure of an inspection unit capable of performing transmission inspection is illustrated in FIG. 11.

[0034] Defects (dark defects and / or clear defects) in the photomask pattern can be identified through transmission inspection and reflection inspection. The optical module itself, which inspects the photomask pattern for defects or foreign substances, is already a well-known structure, so a detailed description thereof is omitted. Various existing optical modules for inspecting patterns or foreign substances in the photomask (360) can be used as the inspection unit (330) of the present embodiment.

[0035] The correction unit (340) corrects defects in the photomask (360). In one embodiment, the correction unit (340) corrects defects by spraying a laser and / or gas. The detailed configuration of the correction unit (340) will be reviewed again in FIG. 7.

[0036] The cleaning unit (350) cleans the photomask (360) using air and / or carbon dioxide. The cleaning unit (350) may perform point dry cleaning, cleaning only the portion where foreign substances exist, rather than cleaning the entire photomask. For example, the cleaning unit (350) may output air to remove foreign substances existing on the photomask (360) or output carbon dioxide to remove foreign substances existing on the photomask (360). Alternatively, the cleaning unit (350) may remove foreign substances using both air and carbon dioxide.

[0037] In one embodiment, the cleaning unit (350) may use a gas or a naturally evaporating substance as a cleaning agent to remove foreign substances from the surface of the photomask (360) while simultaneously preventing residue or stains from remaining on the surface of the photomask. For example, the cleaning unit (350) may remove foreign substances using high-pressure carbon dioxide and high-pressure air. The cleaning unit (350) will be discussed again in FIG. 6.

[0038] In another embodiment, the photomask inspection device may further include a control unit (not shown) for controlling the vertical movement of the inspection unit (330), the correction unit (340), and the cleaning unit (350) attached to the gantry unit (320), the left-right movement of the photomask (360) vertically loaded on the stage unit (310), and the inspection process, the correction process, and the cleaning process. The control unit may be implemented with a processor and a memory. The method of the control unit (not shown) controlling the inspection unit (330), the correction unit (340), the cleaning unit (350), etc. to perform inspection, correction, and cleaning will be discussed again with reference to FIGS. 9 and 10.

[0039] In another embodiment, the photomask inspection device may further include a user interface unit (not shown) for receiving input from the user about the type and / or size of the defect or foreign substance identified by the inspection unit (330). The user interface may be implemented using various existing interfaces such as a touch screen. For example, when the inspection unit (330) detects a defect or foreign substance, the user may check the defect or foreign substance photographed by the inspection unit through the user interface unit (not shown) and input its type and size. The photomask inspection device may determine a correction method and / or a cleaning method based on the type and size of the defect or foreign substance input by the user. Alternatively, the photomask inspection device may directly receive input from the user and store the correction method or cleaning method for each defect or foreign substance.

[0040] In another embodiment, the photomask inspection device can automatically identify the type and size of the defect or foreign substance by pre-defining and storing information on various types of defects or foreign substances and then comparing the images of the defects or foreign substances identified through the inspection unit (330) with the pre-stored information. In another example, the photomask inspection device can use an artificial intelligence model implemented as an artificial neural network to automatically identify the type and size of the defect or foreign substance. In another embodiment, the photomask inspection device can use the optical module of the correction unit (340) for defect review for inspection.

[0041] FIG. 4 is a drawing illustrating another example of a photomask inspection device according to an embodiment of the present invention.

[0042] Referring to Fig. 4, the photomask inspection device includes a stage unit (310) and a gantry unit (400). The photomask inspection device of Fig. 4 has a different structure of the gantry unit (400) compared to the photomask inspection device of Fig. 3, but the configuration of the stage unit (310) and other components are the same.

[0043] The gantry unit (400) of the present embodiment includes one gantry. The gantry unit (400) may include at least one of an inspection unit, a correction unit, and a cleaning unit. For example, only the inspection unit may be attached to the gantry unit (400). Alternatively, the inspection unit and the correction unit may be attached to the gantry unit (400) without a cleaning unit. Alternatively, the inspection unit, the correction unit, and the cleaning unit may all be attached to the gantry unit (400).

[0044] In the gantry section (400), a plurality of pieces of equipment (two or more of an inspection section, a correction section, and a cleaning section) may be implemented as a single module (unit) (400) or implemented separately. For example, the gantry section (400) may have three vertical rails, and the inspection section, the correction section, and the cleaning section may be independently positioned on each rail. As another example, the gantry section (400) may have one rail, and a module (unit) (410) including all of the inspection section, the correction section, and the cleaning section may be present on the rail.

[0045] FIG. 5 is a drawing showing an example of a defect or foreign substance in a photomask inspected by a photomask inspection device according to an embodiment of the present invention.

[0046] Referring to FIG. 5, various types of defects or foreign substances may exist on the surface of the photomask (500) during the manufacturing process. For convenience of explanation, this embodiment is described assuming that the pattern (502) of the photomask (500) exists in a vertical direction, the pattern (502) is implemented with chromium (cr), and the photomask substrate (504) is quartz (Qz).

[0047] There may be a dark defect (515) in which the chromium used to form the pattern in the photomask manufacturing process is outside the pattern (502), a clean defect (520, 522) in which the chromium is not present where the pattern should be, and various types of foreign substances such as dust located on the pattern or substrate (525, 530, 535).

[0048] The photomask inspection device removes foreign substances (525, 530, 535) located on the surface of the photomask through the cleaning process of the cleaning unit. Among the foreign substances (525, 530, 535), there may be some that are simply placed on the surface of the photomask and some that are strongly adhered to the surface of the photomask. Therefore, the cleaning unit of the present embodiment can more effectively remove foreign substances by using high-pressure carbon dioxide and high-pressure air. The cleaning unit sprays high-pressure carbon dioxide and high-pressure air onto the foreign substances (525, 530, 535) through a nozzle. The high-pressure carbon dioxide is sprayed as fine particles through the nozzle and adheres to the foreign substances (525, 530, 535), and the fine particles of carbon dioxide are vaporized together with the foreign substances (525, 530, 535) and removed. The cleaning unit removes contamination by spraying carbon dioxide and air only to areas where foreign substances (525, 530, 535) exist, thereby having the advantage of reducing cleaning time, cost, environmental pollution, etc. compared to the cleaning process of Fig. 2 using chemicals and water. In another embodiment, the size of the fine particles output can be adjusted by adjusting the nozzle diameter and air pressure of the cleaning unit depending on the size of the foreign substances (525, 530, 535).

[0049] A photomask inspection device can correct pattern combinations through a correction unit. For example, the photomask inspection device can remove dark defects (515) by outputting a laser through the correction unit. Furthermore, the photomask inspection device can fill in defect areas by injecting an auxiliary gas into the corresponding area through the correction unit to correct clean defects (520, 522). Since the types of auxiliary gases used to fill in defect areas of a pattern are already widely known, a detailed description thereof will be omitted.

[0050] FIG. 6 is a drawing showing an example configuration of a cleaning unit according to an embodiment of the present invention.

[0051] Referring to FIGS. 3 and 6 together, the cleaning unit (350) includes a first output unit (600), a second output unit (610), a pressure control unit (620), and a nozzle (630). Depending on the embodiment, some components, such as the pressure control unit (620), may be omitted or implemented by adding other components.

[0052] The first output unit (600) injects high-pressure carbon dioxide. In one embodiment, the photomask inspection device includes a storage unit (not shown) for storing high-pressure carbon dioxide on one side, and the first output unit (600) of the cleaning unit (350) may be connected to the storage unit by a hose or the like. Alternatively, the storage unit for storing high-pressure carbon dioxide may be located in the cleaning unit (350). The pressure of the high-pressure carbon dioxide may be set to various values ​​depending on the embodiment, and for example, may be set to several atmospheres. In addition, the high-pressure carbon dioxide may exist in a liquefied state.

[0053] The second output unit (610) injects air. The second output unit (610) is positioned adjacent to the first output unit (600). For example, the second output unit (610) may be positioned to output air toward the carbon dioxide output from the first output unit (600).

[0054] Carbon dioxide output from the first output unit (600) and air output from the second output unit (610) are mixed and output to the outside through the nozzle (630). At this time, the particle size of the carbon dioxide may vary depending on the strength (pressure or speed) of the air output from the second output unit (610).

[0055] The pressure control unit (620) controls the pressure of the air output from the second output unit (610). The pressure control unit (620) can control the intensity of the air output from the second output unit (610) by compressing the air using a compressor or the like. In addition, the structure of the pressure control unit (620) for controlling the pressure of the air can be modified in various ways depending on the embodiment.

[0056] When the pressure control unit (620) increases the pressure of the air, the pressure and speed of the air output from the second output unit (610) increase, and conversely, when the pressure control unit (620) decreases the pressure of the air, the pressure and speed of the air output from the second output unit decrease. The size of the carbon dioxide particles sprayed through the nozzle (630) can be controlled by adjusting the air pressure of the pressure control unit (620).

[0057] The structure of the nozzle (630) can be implemented in various shapes depending on the embodiment. The nozzle (630) can include multiple input portions (632) that each receive air (650) and carbon dioxide (640) and one output portion (634) that outputs air and carbon dioxide. For example, carbon dioxide (640) can be inserted into the center portion of the nozzle (630) and air (650) can be inserted into the edge portion of the nozzle (630), and then the air (650) and carbon dioxide (640) can be mixed at the output portion (634) of the nozzle (630) and sprayed outward.

[0058] In another embodiment, static electricity generated by the use of high-pressure carbon dioxide and air can damage the photomask. To prevent this, an ionizer (not shown) may be installed on one side of the photomask inspection device. For example, the ionizer may be installed on one side of the correction unit (340) or the cleaning unit (350) and moved together with the correction unit (340) or the cleaning unit (350).

[0059] FIG. 7 is a drawing showing an example of a configuration of a modification unit according to an embodiment of the present invention.

[0060] Referring to FIGS. 3 and 7 together, the correction unit (340) includes a laser output unit (710) and a gas output unit (720). The laser output unit (710) outputs a laser to remove hard defects (e.g., dark defects) of the photomask. For example, the laser output unit (710) may output a laser to remove chrome existing outside of the pattern of the photomask. The intensity and type of the laser to remove chrome, etc. may be variously modified depending on the embodiment.

[0061] The gas output unit (720) outputs auxiliary gas to correct a defect (clean defect) in which a pattern is not present at a location where a pattern should be present. The type of auxiliary gas may vary depending on the embodiment.

[0062] In addition to these, various types of optical modules exist for correcting photomask pattern defects. Various existing optical modules for correction can be used as the correction unit of this embodiment, and are not limited to this embodiment.

[0063] FIG. 8 is a drawing showing an example of the arrangement structure of each module for inspection, modification, or cleaning according to an embodiment of the present invention.

[0064] Referring to FIG. 8, the photomask inspection device may include an inspection unit (830), a correction unit (not shown), and a cleaning unit (840). Alternatively, the photomask inspection device may include an inspection unit (830) and a correction unit (not shown), or may include an inspection unit (830) and a cleaning unit (840). For convenience of explanation, the following description assumes that only the inspection unit (830) and the cleaning unit (840) exist.

[0065] The inspection unit (830) and the cleaning unit (840) may be implemented as a single module (unit) and move on a single gantry, or may be implemented separately and move on a single gantry or two independent gantry units. However, for convenience of explanation, the following description assumes that the inspection unit (830) and the cleaning unit (840) independently move up and down on independent gantries (810, 820).

[0066] In order to inspect the photomask (800) for defects or foreign substances, the photomask (800) must be moved left and right and the inspection section (830) must be moved up and down. In addition, in order to clean the photomask (800) of defects or foreign substances, the photomask (800) must be moved left and right and the cleaning section (840) must be moved up and down.

[0067] After cleaning the foreign matter of the photomask (800) through the cleaning unit (840), it can be determined whether the foreign matter has been removed through the inspection unit (830). Since the cleaning unit (840) and the inspection unit (830) are positioned at a certain distance apart, the photomask (800) needs to be moved left and right for cleaning and inspection. For example, after removing foreign matter at a specific location of the photomask (800) through the cleaning unit (840), in order to inspect it, the inspection unit (830) needs to be moved to the corresponding location. In other words, the photomask (800) needs to be moved left and right. If cleaning is not done properly, the photomask (800) needs to be moved back to the location of the cleaning unit for additional cleaning. In other words, there may be a disadvantage in that the photomask needs to be moved every time cleaning and inspection are performed.

[0068] In this embodiment, the direction (angle) of the nozzle (842) of the cleaning unit (840) is adjusted so that both cleaning and inspection can be performed without moving the photomask left and right, and the cleaning position is arranged to match the inspection position of the inspection unit (830). The inspection unit (830) can check the cleaning result by the cleaning unit (840) in real time, and the cleaning unit (840) can immediately perform additional cleaning if additional cleaning is necessary based on the real-time confirmation result of the inspection unit (830). In other words, there is no need to move the photomask (800) to the positions of the inspection unit (830) and the cleaning unit (840) each time.

[0069] In another embodiment, a correction unit (not shown) may be positioned at the location of the cleaning unit (840). In this case, the nozzle of the correction unit (not shown) may also be positioned so as to face the inspection position of the inspection unit (830), so that correction and inspection can be performed simultaneously at one location without moving the photomask left and right.

[0070] In another embodiment, both the cleaning unit (840) and the correction unit may be present together with the inspection unit (830). In this case, the nozzle (842) of the cleaning unit (840) and the nozzle of the correction unit (not shown) may be positioned to face the inspection position of the inspection unit (830), respectively. For example, the cleaning unit (840) and the correction unit (not shown) may be positioned on both sides of the inspection unit (830), and the nozzles (842) of the cleaning unit (840) and the correction unit (not shown) may be positioned to face the inspection position of the inspection unit (830), respectively.

[0071] FIG. 9 is a flowchart illustrating an example of an inspection method of a photomask inspection device according to an embodiment of the present invention.

[0072] Referring to Fig. 9, a cleaning process is performed after pattern generation of the photomask (S900). The pattern generation and cleaning processes of the photomask may be conventional photomask manufacturing processes. Thereafter, the photomask is loaded into a photomask inspection device, and the photomask inspection device performs inspection, cleaning, and / or correction processes of the photomask (S910).

[0073] This embodiment illustrates an example in which a photomask that has undergone a primary cleaning process after pattern generation is loaded into a photomask inspection device. However, this is merely an example, and the photomask loaded into the photomask inspection device may not have undergone a cleaning process. In addition, the photomask may be in various states when loaded into the photomask inspection device, and is not limited to a specific state.

[0074] A photomask inspection device can clean or correct only areas containing defects or foreign substances, without cleaning the entire photomask. This is discussed again in Fig. 10.

[0075] FIG. 10 is a drawing illustrating another example of an inspection method of a photomask inspection device according to an embodiment of the present invention.

[0076] Referring to FIG. 3 and FIG. 10 together, the photomask inspection device inspects a photomask (360) loaded vertically using the inspection unit (330) of the first gantry (322). When the photomask inspection device finds a defect or foreign substance through the inspection unit (330), the device stores the corresponding location (i.e., coordinate value). Hereinafter, the area where the defect or foreign substance exists is referred to as an inspection area. If multiple defects or foreign substances exist on the photomask (360), multiple inspection areas may exist. The photomask inspection device stores the coordinates of each inspection area.

[0077] In one embodiment, the photomask inspection device can inspect the photomask (360) row by row. For example, the position of the inspection unit (330) can be fixed, the photomask (360) can be moved from left to right to inspect one row, and then the position of the inspection unit (330) can be moved vertically by a certain interval, and the photomask can be moved from left to right again to inspect the next row. The vertical position movement interval of the inspection unit (330) can be determined according to the inspection width of the inspection unit (330). In addition, the inspection direction of the photomask can be modified in various ways depending on the embodiment.

[0078] When at least one inspection area (1000, 1010) is identified through the inspection unit (330), the photomask inspection device cleans or corrects each inspection area through the cleaning unit (350) and / or the correction unit (340). For example, the photomask inspection device positions the cleaning unit (350) and / or the correction unit (340) in the first inspection area (1000) and then performs the cleaning process and / or the correction process (1020) for the first inspection area (1000). The photomask inspection device checks the results of the cleaning and / or correction for the first inspection area in real time through the inspection unit (330). When it is confirmed through the inspection unit (330) that the cleaning or correction for the first inspection area (1000) is completed, the photomask inspection device moves the cleaning unit and / or the correction unit to the second inspection area (1010) (i.e., controls the left-right movement of the photomask and the up-and-down movement of the cleaning unit and / or the correction unit). After the removal of defects or foreign substances in the first inspection area (1000) is completed, the process moves to the second inspection area (1010), and after the removal of defects or foreign substances in the second inspection area (1010) is completed, the process moves to the third inspection area.

[0079] In another embodiment, the photomask inspection device may perform a first cleaning process for each inspection area (1000, 1010), and then perform a second correction process if there are defects or foreign substances that are not removed by the cleaning process.

[0080] In another embodiment, the photomask inspection device can select a cleaning process or a correction process depending on the type or size of defects or foreign substances present in each inspection area (1000, 1010). Foreign substances found in photomasks vary greatly in their composition, composition, and size. In the case of metallic foreign substances, laser irradiation can be used to remove them. However, if the foreign substance exists on the pattern, using the laser may re-create a defect that causes the pattern to disappear, and depending on the type of foreign substance, laser irradiation may actually generate adhesive solid foreign substances. Therefore, the correction process can be used for hard defects, and the cleaning process can be used to remove foreign substances in cases where the defects are not hard.

[0081] For example, if a defect existing in the first inspection area (1000) is a dark defect, the photomask inspection device can select a correction process for the first inspection area (1000), and furthermore, select a correction process using laser output among the correction processes. The photomask inspection device can predefine and use the process to be performed (e.g., a cleaning process or a correction process) and the specific method of each process (e.g., particle size of liquefied carbon dioxide, laser output, or auxiliary gas output) according to the type and size of the defect or foreign substance. For example, when a user inputs the type and size of a defect through a user interface, the photomask inspection device can select a predefined cleaning or correction process for the type and size of the defect. Alternatively, the photomask inspection device can automatically identify the type and size of the defect through image analysis or the like, and select a cleaning or correction process accordingly.

[0082] FIG. 11 is a drawing illustrating another embodiment of a photomask inspection device according to an embodiment of the present invention.

[0083] Referring to Fig. 11, a left side view of a photomask inspection device is illustrated. The photomask inspection device of the present embodiment further includes an optical module (1110, 1120) for transmission inspection and securing a transmission correction image compared to the structure of Fig. 3. For convenience of explanation, the present embodiment illustrates the optical module (1110, 1120) for transmission inspection, etc. based on the structure of Fig. 3, but this is only one example, and the structure of Fig. 4 may also further include an optical module for transmission inspection.

[0084] The structure of the gantry unit (320), inspection unit (330), correction unit (340), and cleaning unit (350) located at the front side of the stage unit (1100) is the same as in FIG. 3. In the present embodiment, unlike the structure of FIG. 3, a second gantry unit (1130) exists at the rear side of the stage unit (1100). The number and position of the second gantry unit (1130) may correspond one-to-one with the gantry unit (320). For example, if there are three gantries as in FIG. 3, the second gantry unit (1130) may also include three gantries. The second gantry unit (1130) includes an optical module (1110, 1120) for transmission inspection, etc., located opposite the inspection unit (330) and / or correction unit (340). The optical module (1110, 1120) located in the second gantry section (1130) receives light output from the inspection section (330) and / or the correction section (340) and transmitted through the photomask (360). To this end, the optical module (1110, 1120) is positioned to face the inspection section (330) and / or the correction section (340), and when the inspection section (330) and / or the correction section (340) move, the optical module (1110, 1120) also moves together.

[0085] Fig. 12 is a drawing illustrating another embodiment of a photomask inspection device according to an embodiment of the present invention. Fig. 12 is an example of a front view of a photomask inspection device.

[0086] Referring to Fig. 12, the stage unit (1200) loads a photomask (1250) horizontally. On the front side of the photomask (1250), there is a gantry (1210, 1212, 1214) on which at least one of an inspection unit (1220), a correction unit (1230), and a cleaning unit (1240) is positioned for inspection, correction, or cleaning. For convenience of explanation, the present embodiment assumes that the inspection unit (1220), the correction unit (1230), and the cleaning unit (1240) are all located on independent gantries (1210, 1212, 1214).

[0087] The stage unit (1200) loads the photomask (1250) horizontally and then controls its movement in the left and right directions. Each gantry (1210, 1212, 1214) controls the movement of the inspection unit (1220), the correction unit (1230), and the cleaning unit (1240) in the front and back directions, respectively. At this time, the nozzle directions of the correction unit (1230) and the cleaning unit (1240) can be rotated at a certain angle so as to face the inspection position of the inspection unit. In this case, inspection, correction, and cleaning can all be performed in one place without moving the photomask (1250) or the inspection unit (1220), the correction unit (1230), or the cleaning unit (1240).

[0088] In another embodiment, the inspection unit (1220), the correction unit (1230), and the cleaning unit (1240) can be fixed and the photomask can be moved in the forward, backward, left, and right directions to perform inspection, correction, and cleaning.

[0089] The present invention has been described above, focusing on preferred embodiments thereof. Those skilled in the art will appreciate that the present invention can be implemented in modified forms without departing from its essential characteristics. Therefore, the disclosed embodiments should be considered illustrative rather than limiting. The scope of the present invention is set forth in the claims, not the foregoing description, and all differences within the scope equivalent thereto should be construed as being encompassed by the present invention.

Claims

1. Stage section for loading and moving photomasks; and A photomask inspection device characterized by including a gantry section having at least one of an inspection section, a correction section, and a cleaning section attached thereto for inspection, correction, or cleaning of the photomask on the front side of the photomask.

2. In paragraph 1, The above stage section loads the photomask in a vertical direction and moves the photomask in a left-right direction, A photomask inspection device characterized in that the gantry section is positioned vertically in front of the stage section and moves at least one of the inspection section, the correction section, and the cleaning section in the up-and-down direction.

3. In paragraph 2, A photomask inspection device characterized by further comprising a second gantry unit that is positioned vertically at the rear of the stage unit and moves an optical module located at a position opposite to the inspection unit or the correction unit in the up-and-down direction.

4. In the second paragraph, the gantry section, A first gantry for moving the inspection section in the vertical direction; A second gantry for moving the above-mentioned correction part in the vertical direction; and A photomask inspection device characterized by including a third gantry that moves the cleaning unit in an up-and-down direction.

5. In paragraph 1 or 2, The above correction unit or the above cleaning unit is spaced apart from the inspection unit at a certain distance, A photomask inspection device characterized in that the nozzle of the above correction unit or the nozzle of the above cleaning unit is tilted at a certain angle toward the inspection position of the above inspection unit.

6. In paragraph 1, the cleaning unit, A photomask inspection device characterized by outputting air and / or carbon dioxide through a nozzle.

7. In paragraph 6, the cleaning unit, A first output unit that outputs carbon dioxide; a second output section for outputting air; and A pressure control unit that controls the pressure of air output through the second output unit; A photomask inspection device characterized in that the particle size of carbon dioxide output through the nozzle is controlled according to the pressure of the air.

8. In paragraph 1, the modification part, a laser output unit that outputs a laser; and A photomask inspection device characterized by including a gas output unit that outputs gas.

9. In paragraph 1, A photomask inspection device characterized by further comprising a user interface unit for receiving input from a user of the type and / or size of defects and / or foreign substances identified through the inspection unit.

10. In paragraph 9, A photomask inspection device further comprising a control unit that controls the correction unit and / or cleaning unit according to a cleaning method and / or correction method determined according to the type and / or size of the defect and / or foreign substance.

11. A photomask inspection method performed by a photomask inspection device including a stage section for moving a photomask, and a cabinet section having an inspection section, a correction section, and a cleaning section attached thereto, A step of identifying at least one inspection area in which a defect and / or foreign matter of the photomask exists through movement control of the inspection unit and / or movement control of the photomask; and A photomask inspection method characterized by comprising a step of controlling the correction unit and / or the cleaning unit to correct or clean defects and / or foreign substances in the inspection area.

12. In the 11th paragraph, the step of modifying or cleaning, A step of checking in real time the results of correction and / or cleaning for the first inspection area where defects and / or foreign substances exist through the above inspection unit; A step of repeatedly performing correction and / or cleaning on the first inspection area through the correction unit and / or the cleaning unit until defects and / or foreign substances in the first inspection area are removed through the real-time confirmation; and A photomask inspection method characterized by comprising: a step of performing cleaning and / or correction for a second inspection area by controlling movement of the photomask through the stage unit and controlling movement of the correction unit and / or the cleaning unit through the canister unit when correction and / or cleaning for the first inspection area is completed; 13. In paragraph 11, The step of identifying the above inspection area includes a step of storing the coordinates of the area where a defect and / or foreign substance exists; A photomask inspection method characterized in that the above-mentioned correcting or cleaning step includes a step of moving the correction unit or the cleaning unit to each inspection area according to the coordinates of the previously stored inspection area.

14. In the 11th paragraph, the step of modifying or cleaning, A step of performing cleaning on the inspection area using the cleaning unit; A step of confirming the cleaning results through the inspection unit; and A photomask inspection method characterized by including a step of correcting a defect using the correction unit if a defect still exists after cleaning.

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