TWI639886B - Method for maintaining reticle stage - Google Patents

Abstract

The invention provides a photomask that can be placed on a photomask carrying platform in an exposure device. The photomask includes a substrate and a reflective structure. The substrate includes a main surface and at least one side wall, and the main surface is in contact with the side wall. The main surface includes a pattern region and a peripheral region. The peripheral region is disposed on an outer side of the pattern region. The reflective structure is disposed on at least the side wall surface or the peripheral area of the main surface.

Description

Maintenance method of photomask bearing platform

The invention relates to a photomask and a method for maintaining a photomask carrying platform, and more particularly to a photomask and a method for maintaining a photomask carrying platform that can be used to detect the effectiveness of fixed components on the photomask carrying platform.

Generally, a semiconductor device must be completed by a complicated semiconductor process. Among them, various circuit layouts on a wafer need to be defined by several lithography processes. In the lithography process, the exposure step is performed by an exposure device, which can transfer the circuit layout on the photomask to the wafer. The yield of the exposure process directly affects the manufacturing cost of the wafer. The exposure device Yield has the most direct impact. During the exposure process, any slight deviation of the photomask will interfere and affect the exposure result. If the circuit layout is distorted when transferred to the wafer, the image circuit characteristics will even be defective, which will result in a defective product and reduce the yield. In addition, during the operation of the exposure device, how to reduce the deviation of the position of the photomask to improve the yield is a technical problem urgently solved by those skilled in the art.

The invention provides a photomask and a method for maintaining a photomask carrying platform, which are used to detect the effectiveness of the fixed components on the photomask carrying platform.

An embodiment of the present invention provides a photomask that can be placed in a photomask carried in an exposure device. On the platform, the photomask includes a substrate and a reflective structure. The substrate includes a main surface and at least one side wall, and the main surface is in contact with the side wall. The main surface includes a pattern region and a peripheral region. The peripheral region is disposed on an outer side of the pattern region. The reflective structure is disposed on a side wall surface or a peripheral area of the main surface.

An embodiment of the present invention further provides a method for maintaining a photomask carrying platform, which includes providing a photomask, which is placed on the photomask carrying platform in an exposure device, and the photomask is fixed by a fixing element on the photomask carrying platform. The photomask is fixed on a photomask carrying platform, wherein the photomask carrying platform is a movable platform, and the photomask includes a substrate and a reflective structure. The substrate includes a main surface and at least one side wall, and the main surface is in contact with the side wall. The main surface includes a pattern region and a peripheral region. The peripheral region is disposed on an outer side of the pattern region. The reflective structure is disposed on at least the side wall surface or the peripheral area of the main surface. A first detection step is performed, the photomask carrying platform is moved, and a reflective beam is illuminated by a laser beam to measure a position information of the photomask. A confirmation step is performed to determine whether the photomask is displaced on the photomask bearing platform from the position information. When the photomask is displaced, the performance of the fixed element is judged to be unacceptable, and when the photomask is not displaced, the fixed element is determined. The performance is qualified.

10‧‧‧Exposure device

100‧‧‧ light source

102‧‧‧Photomask carrying platform

104‧‧‧ lens system

106‧‧‧Wafer Carrying Platform

108‧‧‧Fixed components

110, 1101, 1102‧‧‧ interferometer

112‧‧‧ substrate

114‧‧‧ main surface

116, 1161, 1162 ‧‧‧ side walls

118, 1181, 1182‧‧‧ Reflective Structure

120‧‧‧Counting mark

IL‧‧‧illumination light

L1, L2‧‧‧ laser beam

R‧‧‧Photomask

R1‧‧‧Pattern area

R2‧‧‧Peripheral area

R21‧‧‧Edge

R22‧‧‧Inner edge

S100 ~ S114, S102 ’~ S106’, S200 ~ S210‧‧‧ steps

V‧‧‧ vertical projection direction

W‧‧‧ Wafer

X‧‧‧ first direction

Y‧‧‧ second direction

FIG. 1 is a schematic diagram of an exposure apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram of a photomask according to the first embodiment of the present invention.

FIG. 3 is a flowchart of steps in a method for maintaining a mask carrying platform according to the first embodiment of the present invention.

FIG. 4 is a flowchart of steps in a method for maintaining a mask carrying platform according to a modified embodiment of the first embodiment of the present invention.

FIG. 5 is a schematic diagram of a photomask according to a second embodiment of the present invention.

FIG. 6 is a schematic diagram of a photomask according to a third embodiment of the present invention.

FIG. 7 is a schematic diagram of a photomask according to a fourth embodiment of the present invention.

FIG. 8 is a schematic diagram of a photomask according to a fifth embodiment of the present invention.

In order to make a person skilled in the art who is familiar with the technical field of the present invention further understand the present invention, the preferred embodiments of the present invention are enumerated below, and in conjunction with the accompanying drawings, the image sensor of the present invention and the manufacturing method thereof will be described in detail. And the desired effect. For ease of representation and easy understanding, the drawings are not drawn with the actual size or ratio of the finished product, so the sizes or ratios of the components in the drawings are for illustration only and are not intended to limit the scope of the invention.

Please refer to FIG. 1 and FIG. 2. FIG. 1 is a schematic diagram of an exposure apparatus according to a first embodiment of the present invention, and FIG. 2 is a schematic diagram of a photomask according to the first embodiment of the present invention. In order to facilitate the presentation and highlight the main points of the present invention, FIG. 1 only depicts the main elements in the exposure device, and FIG. 2 only depicts the photomask and the corresponding interferometer, and other elements in the exposure device are omitted. As shown in FIG. 1, an exposure apparatus 10 in this embodiment may be, for example, a step exposure apparatus or a scanning exposure apparatus, but is not limited thereto. The exposure apparatus 10 includes a light source 100, a mask carrying platform 102, a lens system 104 and a wafer carrying platform 106. The mask carrier platform 102 is disposed between the light source 100 and the lens system 104, and the lens system 104 is disposed between the mask carrier platform 102 and the wafer carrier platform 106. The light source 100 can emit an illumination light IL as an exposure light source, where the illumination light IL may be, for example, G-line, I-line, KrF quasi-fractional laser light (wavelength 248 nm), ArF Excimer laser light (wavelength 193nm), F2 laser light (wavelength 157nm), etc. The photomask carrying platform 102 can be used to place a photomask R of the present invention, wherein the photomask R may or may not have a pattern (such as a circuit layout diagram). The photomask carrying platform 102 may be provided with a plurality of fixing elements 108 for fixing the photomask R on the photomask carrying platform 102. The fixing element 108 of this embodiment includes a vacuum suction pad, but is not limited thereto. In addition to the attractive fixing element, the fixing element 108 may also include a contact type fixing Components or mechanical fixed components, but not limited to this. The photomask carrying platform 102 has a hollow portion (not shown). When the photomask R is placed on the photomask carrying platform 102, the hollow portion of the photomask carrying platform 102 can expose the pattern of the photomask R, so that light can be by. The wafer carrying platform 106 can be used to place a wafer W, and the wafer carrying platform 106 can also have a fixing element (not shown) for fixing the position of the wafer W. The fixing elements on the wafer carrying platform 106 may include a contact type fixing element, a mechanical type fixing element, or a suction type fixing element. In addition, the mask carrying platform 102 and the wafer carrying platform 106 can be connected to a moving element (not shown), and the photomask carrying platform 102 and the wafer carrying platform 106 can be moved by the moving elements, respectively. In other words, the photomask carrying platform 102 and the wafer carrying platform 106 in this embodiment may be movable platforms, and the moving elements may be linear motors, but not limited thereto. The lens system 104 includes a lens group composed of one or more lenses, and a lens combination in the lens system 104 can be selected according to the requirements of an actual exposure process. In this embodiment, the illumination light IL first forms an image through the mask R, and this image corresponds to the pattern of the mask R. This image (or illumination light IL) then enters the lens system 104 and is imaged on the surface of the wafer W through the lens system 104. For example, through the illumination light IL and the lens system 104, the pattern on the photomask R can be transferred to a photosensitive layer (such as a photoresist) on the wafer W.

The related technical features of the mask R and how to measure the position of the mask R in this embodiment will be described in detail below. As shown in FIG. 2, the photomask R includes a substrate 112 including a main surface 114 and at least one side wall 116, and the main surface 114 is connected to the side wall 116. In detail, if the traveling direction (or optical axis) of the illumination light IL in FIG. 1 is regarded as a vertical projection direction V, the main surface 114 and the vertical projection direction V of the mask R in this embodiment are perpendicular to each other, but not This is the limit. The main surface 114 of the substrate 112 includes a pattern region R1 and a peripheral region R2. The pattern region R1 may have a pattern (such as a circuit layout diagram). The peripheral region R2 is disposed on an outer side of the pattern region R1. In this embodiment, the peripheral region R2 surrounds the pattern region R1. It should be noted that although the main surface 114 of the substrate 112 in this embodiment refers to the upper surface of the photomask R shown in FIG. 2, it depends on the viewing direction, the setting method, or the design of each photomask. In the embodiment, the main surface 114 It may also represent the lower surface of the mask R. In other words, the main surface 114 referred to in this embodiment is not limited to the upper surface or the lower surface of the mask R. On the other hand, the substrate 112 includes four side walls 116, of which two side walls 1161 parallel to each other are perpendicular to a first direction X, and two side walls 1162 parallel to each other are perpendicular to a second direction Y, and the first direction X Both are perpendicular to the second direction Y and perpendicular to the vertical projection direction V. In addition, the photomask R in this embodiment further includes a reflective structure 118 disposed on a part of the surface of the sidewall 116. In detail, the photomask R of this embodiment includes four reflective structures 118, of which two reflective structures 1181 are disposed on one side wall 1161, and two other reflective structures 1182 are disposed on one side wall 1162. In other words, the reflective structure 1181 is also perpendicular to the first direction X, and the reflective structure 1182 is also perpendicular to the second direction Y. As shown in FIG. 2, each reflective structure 118 in this embodiment occupies a part of its corresponding side wall 116, and is separated from each other and does not overlap. The reflective structure 118 of this embodiment includes a bar mirror, and its shape is rectangular, but it is not limited thereto, and an appropriate shape can be selected according to requirements. In addition, the material of the substrate 112 may include quartz, and the material of the reflective structure 118 may include a reflective material, such as a metal material, but is not limited thereto. For example, the sidewall 116 of the substrate 112 may be processed to form a reflective structure 118. In one embodiment, the reflective structure 118 can be formed by forming a reflective material (such as metal) on a proper position of the sidewall 116 through a coating process. In another embodiment, a reflective mirror product (such as a strip-shaped mirror) can be adhered to an appropriate position of the side wall 116 to form the reflective structure 118. However, the materials of the substrate 112 and the reflective structure 118 and the processing method of the reflective structure 118 in this embodiment are not limited to the above. In addition, the weight of the photomask R having the reflective structure 118 in this embodiment is substantially the same as that of a photomask conventionally used in an exposure device. It is additionally noted that, in other embodiments, the photomask R may only be used as a photomask for testing, and the pattern region R1 may not have a pattern (such as a circuit layout diagram).

As shown in FIG. 1 and FIG. 2, in this embodiment, the exposure device 10 further includes at least one interferometer 110 that can measure the position information of the photomask R. In detail, as shown in FIG. 2, each of the reflection structures 118 corresponds to an interferometer 110, and the interferometer 110 may be based on a laser beam L1 emitted to the reflection structure 118. And a laser beam L2 reflected by the reflection structure 118 to measure the position information of the mask R. In this embodiment, two interferometers 1101 are respectively disposed in the first direction X corresponding to the reflective structure 1181, and the other two interferometers 1102 are respectively disposed in the second direction Y corresponding to the reflective structure 1182. Therefore, regardless of whether the mask R is moving or stopped, the position information of the mask R in the first direction X and the second direction Y can be measured at any time through the interferometer 1101 and the interferometer 1102 to measure the mask. Whether R is displaced along the first direction X and the second direction Y on the mask carrying platform 102.

It is worth mentioning that the configuration of the reflective structure 118 is not limited to this embodiment. For example, if the movement of the mask R only involves the movement in the first direction X, a reflection structure 1181 may be provided only on the side wall 1161 to measure the position information through the interferometer 1101. If the movement of the mask R involves the movement in the first direction X and the second direction Y at the same time, a reflection structure 1181 and a reflection structure 1182 may be provided on the side walls 1161 and 1162 to measure the position information through the interferometer 1101 and the interferometer 1102. According to the above principles, in one embodiment, only one reflective structure 1181 may be provided on the side wall 1161, and only one reflective structure 1182 may be provided on the side wall 1162. In another embodiment, only one of the four sidewalls 116 may be provided with a reflective structure 118. In addition, the number of the reflective structures 118 may vary according to actual needs. The number of the reflective structures 118 may be changed, for example, according to the number of the interferometer 110 or the laser beam L1. The number can also be changed according to actual needs. For example, an interferometer 110 corresponds to several reflective structures 118 at the same time. In some embodiments, the interferometer 110 can also be used to measure the position of the mask carrying platform 102. In this case, the photomask carrying platform 102 must also be provided with a reflective structure, and the laser beam can be directed to the photomask R and the photomask carrying platform 102 by setting one or more beam splitters to measure the measurement light separately. Position information of the mask R and the mask carrying platform 102.

As shown in FIG. 2, in this embodiment, the photomask R may further include a plurality of alignment marks 120 disposed on the peripheral surface R2 of the main surface 114 (such as the upper surface). Since the material of the mask R in this embodiment is stone In order to make the photomask R transparent, the alignment mark 120 of the photomask R and the alignment mark on the wafer carrying platform 106 can be aligned, so that the appropriate position on the wafer W can be exposed. The alignment marks 120 in this embodiment are arranged on the main surface 114 along the first direction X near the pattern region R1, but not limited thereto.

Please refer to FIG. 3 and refer to FIG. 1 and FIG. 2 together, where FIG. 3 is a flowchart of steps of a method for maintaining a photomask bearing platform according to the first embodiment of the present invention. As shown in FIG. 3, in the method for maintaining the mask carrying platform 102 of this embodiment, after the exposure process of a batch of products is completed (step S100), step S102 is performed to provide the above-mentioned photomask R, and then Placed on the reticle carrying platform 102 of the exposure device 10, and fixing the photomask R on the reticle carrying platform 102 with the fixing element 108 on the reticle carrying platform 102, where the fixing element 108 of this embodiment is a vacuum suction The photomask carrying platform 102 is a movable platform. Next, step S104 is performed, a first detection step is performed, the photomask carrying platform 102 is moved, and the reflective structure 118 is illuminated by the laser beam L1 to measure the position information of the photomask R. For example, as shown in FIG. 2, in this embodiment, the interferometer 1101 and the interferometer 1102 respectively analyze the laser beam L1 and the laser beam L2 to obtain two-dimensional position information of the mask R. As described above, in other embodiments, the first detection step may also measure the position information in one dimension in the first direction X or the second direction Y only through the interferometer 110, and will not be described again.

Next, step S106 is performed, and a confirmation step is performed to determine whether the photomask R is displaced on the photomask bearing platform 102 from the obtained position information. When the photomask R is displaced, it is determined that the performance of the fixing element 108 is unsatisfactory. When the mask R is not displaced, it is determined that the performance of the fixing element 108 is acceptable. In detail, the confirmation step includes, for example, monitoring the position information obtained through the interferometer 1101 and the interferometer 1102 during the movement of the photomask R. When the position information obtained by the interferometer 1101 and the interferometer 1102 changes abnormally (for example, the signal jumps), it is determined that the mask R is displaced. Conversely, when the interferometer 1101 and the dry When there is no abnormal change in the position information obtained by the counter 1102 (for example, the signal remains stable), it is determined that the mask R has not been displaced. In addition, the first detection step and the confirmation step can be performed simultaneously. For example, when the photomask carrying platform 102 drives the photomask R to move, the interferometer 1101 and the interferometer 1102 measure the position information of the photomask R and monitor the position information for abnormal changes at any time. , But not limited to this. In this embodiment, since the fixing element 108 is a vacuum suction pad, if the vacuum suction pad is not clean enough, particles (such as dust and the like) on the vacuum suction pad will destroy the vacuum state and weaken the suction force of the vacuum suction pad, affecting the fixed element 108 The efficiency of the fixed photomask R causes the photomask R to be displaced on the photomask carrying platform 102, thereby causing a change in the signal detected by the interferometer, so there will be unqualified results in the confirmation step. In other words, if the vacuum suction pad is clean, the vacuum suction pad can maintain a vacuum state and provide sufficient suction power. At this time, the performance of the fixed element 108 can be regarded as qualified, and it can effectively fix the light when the photomask carrying platform 102 moves. Hood R.

In addition, when the result of the confirmation step shows that the mask R is not displaced or the effectiveness of the fixed element 108 is determined to be qualified, the cleanliness of the fixed element 108 may be determined to be qualified. At this time, step S108 may be performed to perform an exposure process for the next batch of products. For example, a product mask is provided to replace the mask R on the original mask carrying platform 102, and the product mask is used for exposure. On the other hand, when the result of the confirmation step shows that the photomask R is displaced or the effectiveness of the fixing element 108 is judged to be unsatisfactory, the cleanliness of the fixing element 108 may be deemed to be unsatisfactory. At this time, step S110 may be performed to clean the fixing element 108. After cleaning, step S102 '(provide photomask R), step S104' (perform first detection step), and step S106 '(perform confirmation step), and the contents of steps S102' to S106 'can be the same as steps S102 to Step S106 is the same, and is not repeated here. Then, when the confirmation result of step S106 'still shows that the mask R is displaced or the effectiveness of the fixed element 108 is judged to be unqualified, the above steps S102' to S106 'are repeated until the result of the confirmation step shows that the mask R is not displaced Or it is judged that the performance of the fixing element 108 is qualified.

On the other hand, when the confirmation result of step S106 'shows that the mask R is not displaced or the effectiveness of the fixed element 108 is determined to be acceptable, the cleanliness of the fixed element 108 may be determined to be acceptable. At this time, step S112 can be continued, a preventive maintenance (PM) mask is provided to replace the mask R on the original mask carrying platform 102, and a second inspection step is performed by using the pre-maintenance mask. Next, a confirmation step S114 is performed to confirm whether the exposure pattern formed on the wafer W by the exposure device 10 is distorted or distorted. If it is confirmed that the exposure pattern is not deformed, step S108 is performed to perform the exposure process for the next batch of products. If the exposure pattern is confirmed to be deformed, return to step S110 to clean the fixing element 108, and continue the steps after step S110.

In the exposure process, if the fixed components (vacuum suction pads) on the photomask carrying platform are not clean enough and particles (such as dust) are present, the photomask is easily displaced during the movement of the photomask carrying platform. Although the mask is only slightly displaced, the pattern exposed on the wafer may be deformed or distorted, and the yield may be reduced. Since the conventional exposure device does not have the function of detecting the cleanliness of the fixed component, the fixed component on the photomask bearing platform can only be cleaned after the failure of the exposure result is learned, resulting in waste of resources and increased manufacturing costs. In addition, every time the exposure device is cleaned, it needs to be inspected with a pre-maintenance mask. If the fixed element is not cleaned and the exposure pattern is deformed or distorted again, it needs to be cleaned and inspected again with a pre-maintenance mask . Because the exposure device is stopped for cleaning and restarted to pre-maintain the photomask for inspection, it usually takes one to several hours. If the cleanliness of the fixed components on the photomask bearing platform cannot be determined effectively, the above process needs to be repeated, which will waste many processes. Time and cost. According to the present invention, through the photomask R of this embodiment and the method for maintaining the photomask carrying platform 102 using the photomask R, it is possible to effectively confirm the performance of the fixed element 108 on the photomask carrying platform 102 or whether the fixed element 108 is clean. In addition, it takes only about two to three minutes for the interferometer 110 to measure whether the photomask R is displaced during the movement of the photomask carrying platform 102. Thereby, through the photomask R of this embodiment and the method for maintaining the photomask carrying platform 102 using the photomask R, it is possible to effectively reduce Reduce the number of inspections with the pre-maintenance mask to save time and reduce costs. Therefore, the maintenance method of the mask carrying platform 102 in this embodiment can be performed before each batch of products is subjected to the exposure process or during the periodic maintenance process of the exposure device 10.

The maintenance method of the photomask and the photomask carrying platform of the present invention is not limited to the above embodiments. The following will continue to disclose other embodiments and variations of the present invention, but in order to simplify the description and highlight the differences between the embodiments, the same elements are labeled with the same reference numerals in the following, and the repeated parts will not be repeated.

Please refer to FIG. 4, which is a flowchart of steps in a method for maintaining a mask carrying platform according to a modified embodiment of the first embodiment of the present invention. As shown in FIG. 4, in this modified embodiment, when the exposure process is performed using the exposure device 10 and an exposure failure is found (step S200), the method for maintaining the photomask bearing platform 102 of the present invention can be performed. The cases where the exposure failure is found in the above step S200 include, for example, that during the production of the product, the exposure result of the exposure process is not ideal (for example, the pattern exposed or deformed on the wafer W is deformed or distorted) or the cycle is performed in the exposure device 10 During the sexual maintenance, the pattern formed by the exposure through the pre-repair maintenance mask is deformed or distorted, but it is not limited thereto. In this case, the maintenance method includes first performing step S202, first cleaning the fixing element 108 on the photomask carrying platform 102, and then performing step S204, providing the photomask R of the present invention to the photomask carrying platform 102 and performing The first detection step S206 and the confirmation step S208. The content of the above steps S204 to S208 is the same as or similar to steps S102 to S106 of the first embodiment, and details are not described herein again. In addition, the operation of this modified embodiment after confirming step S208 is also the same as or similar to that of the first embodiment. After confirming step S208, if it is determined that the performance of the fixed element 108 is unsatisfactory, step S202 is performed, and the fixed element 108 is repeatedly cleaned), and after cleaning, the first detection step S206 and the confirmation step S208 are performed. After confirming step S208, if it is determined that the performance of the fixing element 108 is qualified, go to step S210 to provide a pre-repair maintenance mask to replace the light on the mask bearing platform 102 The mask R is subjected to a second detection step using a pre-maintenance mask to determine whether the exposure pattern formed by the exposure device 10 is deformed. For the actions after the second detection step, refer to the first embodiment, and details are not described herein again.

Please refer to FIG. 5, which is a schematic diagram of a photomask according to a second embodiment of the present invention. As shown in FIG. 5, this embodiment is different from the first embodiment in that the reflective structure 118 is disposed on a part of the surface of the peripheral region R2 of the main surface 114. In detail, the peripheral region R2 of this embodiment includes an edge portion R21 and an inner edge portion R22, the edge portion R21 is connected to the side wall 116, and the inner edge portion R22 is disposed between the pattern region R1 and the edge portion R21, wherein The reflective structure 118 is disposed on a part of the surface of the edge portion R21, and the alignment mark 120 is disposed on the inner edge portion R22. In this embodiment, the main surface 114 provided with the reflective structure 118 is the upper surface of the substrate 112, and the interferometer 110 is disposed above the substrate 112 and corresponds to the reflective structure 118 in the vertical projection direction V. Thereby, when the mask carrying platform 102 and the mask R disposed thereon are moved in the vertical projection direction V, the interferometer 110 can be used to transmit the laser beams L1 and L2 and the corresponding reflection structure 118 to measure the mask. The position information of R in the vertical projection direction V, to further know whether the mask R is displaced in the vertical projection direction V and judge whether the vacuum suction pad is clean according to this. In some embodiments, this design can also be used, for example, with a beam splitter to guide the laser beams L1 and L2 to the reflective structure 118 of the side wall 116. Then, the mask R can also be measured in the first direction X or the second direction Y Whether displacement occurs. The number and design positions of the reflective structures 118 and the interferometer 110 may be different according to requirements, and may be disposed on the edge portions R21 on different sides of the substrate 112. In other embodiments, the main surface 114 provided with the reflective structure 118 may be the lower surface of the substrate 112 as required, and the interferometer 110 is correspondingly disposed below the substrate 112. In this case, since the vacuum suction pad of the photomask carrying platform 102 attracts the lower surface of the substrate 112, the position of the reflective structure 118 should be avoided from the position of the vacuum suction pad in the lower surface of the substrate 112.

Please refer to FIG. 6, which is a schematic diagram of a photomask according to a third embodiment of the present invention. As shown in Figure 6 As shown, this embodiment is different from the first embodiment in that the reflective structure 118 covers a side wall 116 over the entire surface. In this embodiment, the reflective structure 118 is disposed on one of the two side walls 1161 perpendicular to the first direction X and covers the entire side wall 1161, so that the laser beams L1 and L2 can be analyzed through the corresponding interferometer 110. The position information of the photomask R in the first direction X is measured. In addition, the reflective structure 118 can also be disposed at the same time and cover the two side walls 1161 on the entire surface. In other embodiments, if the position information of the photomask R in the second direction Y is to be measured, the reflective structure 118 may be disposed on at least one sidewall 1162 perpendicular to the second direction Y and cover the sidewall 1162 over the entire surface. To measure the position information of the photomask R in the first direction X and the second direction Y at the same time, the reflective structure 118 may be disposed on the at least one side wall 1161 and the at least one side wall 1162, and cover the side wall 1161 and the side wall 1162 on the entire surface. . According to this embodiment, since the reflective structure 118 covers the entire side wall 1161 or 1162 on the entire surface, the corresponding compatibility of the interferometer 110 and the laser beams L1 and L2 can be provided by the compatibility of the photomask R. More generous. When the installation position of the interferometer 110 varies with different types or brands of exposure devices, the photomask R with high compatibility in this embodiment can be applied to more types or brands of exposure devices.

Please refer to FIG. 7, which is a schematic diagram of a photomask according to a fourth embodiment of the present invention. As shown in FIG. 7, this embodiment is different from the second embodiment in that the edge portion R21 surrounds the pattern region R1 and the entire surface of the reflective structure 118 covers the edge portion R21, that is, the four sides of the reflective structure 118 along the main surface 114 The sides surround the pattern region R1 and the inner edge portion R22. Since the reflective structure 118 is formed of a reflective material, the edge portion R21 of the photomask R is an opaque area, and the pattern area R1 and the inner edge portion R22 are a light-transmissive area, and the registration mark 120 is set. At the inner edge portion R22, the alignment mark 120 can be aligned with the alignment mark on the wafer W. Since the reflective structure 118 of this embodiment covers the entire edge portion R21, the compatibility provided by the photomask R is relatively wide for the positions that can be set by the corresponding interferometer 110 and the laser beams L1 and L2. . When the installation position of the interferometer 110 varies with different types or brands of exposure devices, the photomask R with high compatibility in this embodiment can be applied to more types or brands of exposure devices. in In other embodiments, the reflective structure 118 may cover only the entire surface of the edge portion R21 on any one side, any two sides, or any three sides of the main surface 114. The main surface 114 provided with the reflective structure 118 in this embodiment is the upper surface of the substrate 112. In other embodiments, the main surface 114 provided with the reflective structure 118 may also be the lower surface of the substrate 112 as required. In this case, since the vacuum suction pad of the photomask carrying platform 102 attracts the lower surface of the substrate 112, the position of the reflective structure 118 should be avoided from the position of the vacuum suction pad in the lower surface of the substrate 112.

Please refer to FIG. 8, which is a schematic diagram of a photomask according to a fifth embodiment of the present invention. As shown in FIG. 8, in this embodiment, the reflective structure 118 is disposed on the four side walls 116 of the substrate 112 and covers the entire side wall 116. At the same time, the reflective structure 118 is also disposed on the edge portion R21 of the main surface 114. The structure 118 covers the entire edge portion R21 and surrounds the inner edge portion R22 and the pattern region R1 over the entire surface. In addition, the main surface 114 may be an upper surface or a lower surface of the substrate 112, and the reflective structure 118 may also be disposed on the upper surface and the lower surface of the substrate 112 at the same time. Thereby, the interferometer 110 can be set corresponding to the mask R in the first direction X, the second direction Y or the vertical projection direction V, and the laser beams L1 and L2 can be analyzed by the interferometer 110 to measure the mask R in the first direction. Position information in X, second direction Y, or vertical projection direction V. In addition, when the reflective structure 118 is disposed on the lower edge R21, the vacuum suction pad of the photomask supporting platform 102 attracts the lower surface of the substrate 112. Therefore, the reflective structure 118 should be located away from the substrate 112. The position in the lower surface corresponding to the vacuum suction pad. Since the reflective structure 118 of this embodiment covers the entire surface of the edge portion R21 and the side wall 116 of the surface 114, the corresponding position of the interferometer 110 and the laser beams L1 and L2 can be provided by the photomask R. Compatibility is more generous. When the installation position of the interferometer 110 varies with different types or brands of exposure devices, the photomask R with high compatibility in this embodiment can be applied to more types or brands of exposure devices.

It is worth mentioning that, without exceeding the spirit of the present invention, the Different technical features can be replaced with each other and re-matched to form another embodiment.

To sum up, the photomask of the present invention and the method for maintaining the photomask carrying platform using the photomask can effectively confirm the photomask fixing performance of the fixed components (such as vacuum suction pads) on the photomask carrying platform, and further understand Cleanliness of the surface of the mounting element or reticle carrying platform. In addition, it takes only about two to three minutes to measure whether the photomask is displaced during the movement of the photomask carrying platform using an interferometer, and the interferometer provided with the conventional exposure device itself can be used with the present invention. The reflective structure of the photomask to know whether the photomask is displaced. Thereby, the maintenance method of the photomask and the photomask bearing platform of this embodiment can effectively reduce the number of times that the pre-maintenance photomask is used for inspection, thereby effectively saving time and reducing costs. In addition, the photomask of the present invention may have a reflective structure that covers the entire surface or part of the sidewall of the photomask, or a reflective structure that covers the entire surface or part of the upper and lower edges of the photomask. In the design of the entire surface, The photomask of the present invention can provide relatively wide compatibility, and can be applied to more types or brands of exposure devices.

The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the scope of patent application of the present invention shall fall within the scope of the present invention.

Claims (6)

A method for maintaining a photomask carrying platform includes: providing a photomask placed on a photomask carrying platform in an exposure device, and fixing the photomask to the photomask using a fixing element on the photomask carrying platform. The photomask carrying platform, wherein the photomask carrying platform is a movable platform, and the photomask includes: a substrate including a main surface and at least one side wall, the main surface being connected to the side wall, wherein the main surface includes : A pattern area; and a peripheral area disposed on an outer side of the pattern area; and a reflective structure disposed at least on the side wall surface or the peripheral area on the main surface; performing a first detection step to move the light A mask carrying platform, and irradiating the reflective structure through a laser beam to measure a position information of the mask; and performing a confirmation step to determine whether the mask is displaced on the mask bearing platform from the position information, when When the photomask is displaced, the performance of the fixed element is judged to be unsatisfactory, and when the photomask is not displaced, the performance of the fixed element is judged to be pass, where When the performance of the defective element, the fixing element is cleaned, and providing the reticle and again after the cleaning step of the first detecting step and the acknowledgment. The method for maintaining a reticle carrying platform according to claim 1, wherein the fixing element includes a vacuum pad. The method for maintaining a photomask carrying platform according to claim 1, wherein when the performance of the fixing element is qualified, a product photomask is provided and exposed using the product photomask. The method for maintaining a mask carrying platform according to claim 1, wherein when the performance of the fixed component is determined to be qualified after performing the confirmation step again, a preventive maintenance (PM) mask is provided for a second inspection Step to determine whether a exposure pattern formed by the exposure device is distorted. The method for maintaining the photomask carrying platform according to claim 1, is performed when the exposure device performs an exposure process and finds that the exposure fails, and the maintenance method further includes cleaning the fixing element on the photomask carrying platform Before providing the photomask to the photomask carrying platform and performing the first detection step and the confirmation step. The method for maintaining a photomask carrying platform according to claim 1, wherein the first detecting step comprises measuring the position information of the photomask through an interferometer through the laser beam and the corresponding reflection structure.