TWI760133B - Photomask cleaning apparatus and method - Google Patents

Abstract

A photomask cleaning apparatus used to a photomask box is provided. The photomask box includes an upper cover and a chassis. A photomask is on the chassis. The photomask includes a mask protective film. The photomask cleaning apparatus includes a main housing, a secondary housing, a light cover opening device, a transport device, and at least one air knife device. The secondary housing is connected to the main housing. The light cover opening device includes a lifting element and an opening element. The opening element includes a back connecting part and a cover part. The lifting element is used to lift the back connecting part. The cover part is embedded in the secondary housing. A mask entrance is formed by the cover part and the back connecting part. The upper cover is against the cover part. The transport device includes a slide rail and a mask box carrier platform. The mask box carrier platform is moved to the mask entrance via the slide rail. When the lifting element lifts the light cover opening device, the upper cover, the cover part, the main housing, and the secondary housing form a closed space.

Description

Mask cleaning equipment and mask cleaning method

The present invention relates to a photomask cleaning device and a photomask cleaning method, in particular to a photomask cleaning device and a photomask cleaning method for removing contaminants on a photomask protective film.

In the semiconductor manufacturing process, an exposure process is included. First, a mask with a pattern is placed on the wafer, and then an exposure light source is used to emit light on a wafer through the mask. After that, the wafer is immersed in a developing solution, and the pattern of the reticle can be seen on the wafer.

There is a layer of protective film on the photomask, which can prevent the photomask from being scratched. In addition, since the photomask protective film may adhere to contaminants (contamination particles), chemical substances, etc. due to static electricity, the photomask protective film needs to be cleaned so as not to affect the yield of the semiconductor process. However, it is still necessary to improve the dust removal effect and dust removal efficiency of the existing photomask protective films. In addition, in the process of taking out the photomask, the external contamination particles are also easily attached to the photomask protective film.

Therefore, how to improve the above-mentioned problems is worth thinking about by those with ordinary knowledge in this field.

The purpose of the present invention is to provide a mask cleaning device, which has an excellent dust removal effect on the mask film, and can prevent external pollution particles from adhering to the mask during the process of taking out the mask on the protective film.

The mask cleaning device of the present invention is applied to a mask box. The mask box includes an upper cover and a bottom plate. A mask is accommodated on the bottom plate. The mask has a mask protective film. The mask cleaning device includes a main shell. A body, a primary casing, a mask opening device, a conveying device and at least one air knife device, and the secondary casing is connected to the main casing. Wherein, the mask opening device includes a lifting element and a cover opening element, and the cover opening element includes a rear The back connecting part and a cover part are used for lifting and lowering the back connecting part and the cover part. In addition, the cover part is embedded in the sub-casing, the cover part and the back connecting part form a mask entrance, and the upper cover is abutted on the cover part. In addition, the transporting device includes a slide rail and a photomask box mounting platform. The reticle carrier is moved to the reticle entrance via the slide rail, and the chassis is set on the reticle carrier. In addition, the air knife device is used to generate an air flow to the photomask protective film. Wherein, when the lifting element lifts up to open the cover element, the upper cover, the cover part, the main casing and the secondary casing form a closed space.

In the above-mentioned mask cleaning equipment, the air knife device includes an orientation adjustment element and an air knife nozzle, and the air knife nozzle is connected to the orientation adjustment element.

In the above-mentioned mask cleaning device, the azimuth adjustment element includes a first axis, the air knife nozzle includes a second axis, and the first axis is perpendicular to the second axis.

In the above-mentioned mask cleaning equipment, the number of the air knife devices is multiple, and these air knife devices are arranged in a ㄇ shape.

The above-mentioned photomask cleaning equipment further includes an electrostatic neutralization device, which produces a plurality of charged particles with a plurality of alpha particles, and the charged particles are transmitted to the photomask protective film through a clean gas .

In the reticle cleaning apparatus described above, wherein the chassis includes a rotary switch, and the reticle pod mount includes a rotary unit corresponding to the rotary switch.

The above-mentioned photomask cleaning device further includes an ultrasonic resonance device for generating an ultrasonic wave to the photomask protective film.

The above-mentioned mask cleaning apparatus further includes at least one flow control device for controlling the flow of air entering the air knife nozzle.

In the above-mentioned mask cleaning equipment, the frequency of the ultrasonic wave is not less than 20kHz. In the above-mentioned mask cleaning equipment, the ultrasonic resonance device includes a height adjustment platform and an ultrasonic vibration head, and the ultrasonic vibration head is connected to the height adjustment platform.

The above-mentioned reticle cleaning equipment further includes a reticle film monitoring device, which is used for monitoring the amplitude of the reticle film.

The above-mentioned mask cleaning apparatus further includes at least one air filter device for filtering the contamination particles in the main casing.

Another object of the present invention is to provide a mask cleaning method, which has an excellent dust removal effect on the mask film, and can prevent external pollution particles from adhering to the mask during the process of taking out the mask on the protective film.

The mask cleaning method of the present invention is applied to the above-mentioned mask cleaning equipment, and the mask cleaning method includes the following steps. First, place a mask box to the mask entrance, the mask box includes an upper cover and a bottom plate, and the bottom plate is used for accommodating a mask. After that, the upper cover and the chassis are separated, so that only the chassis and the photomask are carried on the reticle pod loading platform. After that, move the chassis and photomask into the main housing. Afterwards, an airflow is generated to a reticle cover of the reticle. Afterwards, return the chassis and reticle to the reticle inlet. After that, the upper cover is combined with the chassis, so that the photomask is accommodated in the photomask box.

The above-mentioned photomask cleaning method further includes an electrostatic neutralization step, wherein a plurality of alpha particles are used to produce a plurality of charged particles, and the charged particles are transmitted to the photomask protective film through a clean gas.

The above-mentioned photomask cleaning method further includes an ultrasonic resonance step for generating an ultrasonic wave to the photomask protective film.

The invention has the following advantages: it has excellent dust removal effect, and can prevent external pollution particles from adhering to the protective film of the photomask during the process of taking out the photomask.

In order to make the above-mentioned features and advantages of the present invention more obvious and easy to understand, preferred embodiments are exemplified below, and are described in detail as follows in conjunction with the accompanying drawings.

10: Reticle cleaning equipment

11: Main shell

12: Secondary shell

13: Photomask opening device

131: Lifting components

132: Open cover element

132B: Back joint

132C: Cover part

132E: reticle entrance

14: Transporter

141: Slide rail

142: Reticle Cassette Mounting Stage

142S: Rotary unit

15: Air knife device

151: Azimuth adjustment element

151A: The first axis

152: Air Knife Nozzle

152A: Second axis

16: Static neutralization device

161: Ion nozzle

162: Alpha Ionizer

17: Ultrasonic resonance device

171: Height Adjustment Platform

172: Ultrasonic Concussion Head

18: Flow control device

19:Reticle film monitoring device

21: Air filter device

8: Photomask box

81: upper cover

81T: Tenon seat

82: Chassis

82T: Tenon

82S: Rotary switch

83: Photomask

83F: Photomask Protector

S1~S8: Steps

FIG. 1A is a schematic diagram illustrating that the air knife device, the conveying device, the ultrasonic resonance device, the electrostatic neutralization device and the flow control device are located in the main casing.

FIG. 1B is a perspective view of the mask cleaning apparatus.

FIG. 1C is a perspective view of the top cover and the chassis of the photomask box.

FIG. 1D is a schematic view of the bottom surface of the photomask box.

FIG. 2A is a schematic diagram of a mask opening device.

FIG. 2B is a schematic diagram of the cover-opening element rising.

FIG. 3A is a schematic diagram of the transport device.

FIG. 3B is a schematic view of the mask box embedded in the mask inlet.

FIG. 3C is a schematic diagram of the cover opening element opening the upper cover.

FIG. 3D is a schematic diagram illustrating that the chassis is disposed on the photomask pod loading platform.

FIG. 4 is a schematic diagram illustrating the movement of the chassis and the photomask into the main housing.

FIG. 5 is a schematic diagram of three sets of air knife devices.

FIG. 6 is a schematic diagram of an electrostatic neutralization device.

FIG. 7 is a schematic diagram of an ultrasonic resonance device.

FIG. 8 is a flowchart of the mask cleaning method of the present embodiment.

FIG. 9 is a flowchart illustrating a method for cleaning a photomask according to another embodiment.

Please refer to FIGS. 1A , 1B, 1C and 1D. FIG. 1A shows that the air knife device 15 , the conveying device 14 , the ultrasonic resonance device 17 , the electrostatic neutralization device 16 and the flow control device 18 are located in the main casing 11 1B is a perspective view of the mask cleaning apparatus 10, FIG. 1C is a perspective view of the upper cover 81 and the chassis 82 of the mask box 8, and FIG. 1D is a schematic diagram of the bottom surface of the mask box 8. . The mask cleaning apparatus 10 of this embodiment is applied to a mask box 8. The mask box 8 includes an upper cover 81 and a chassis 82. The upper cover 81 includes a plurality of tenon seats 81T, and the side of the chassis 82 includes a plurality of There are ten tenons 82T, and the adjacent tenon 82T corresponds to one tenon seat 81T. Also, the bottom surface of the chassis 82 includes a rotary switch 82S. Among them, when the upper cover 81 knot When combined with the chassis 82, the chassis 82 is covered by the upper cover 81, and the tenon 82T is embedded in the corresponding tenon seat 81T. In addition, the top of the chassis 82 is for accommodating a photomask 83, and the photomask 83 has a photomask protective film 83F.

The mask cleaning apparatus 10 of this embodiment includes a main casing 11, a primary casing 12, a mask opening device 13, a transport device 14, three sets of air knife devices 15, an electrostatic neutralization device 16, a supercharger The sonic resonance device 17 , a plurality of flow control devices 18 , a mask film monitoring device 19 and a plurality of air filter devices 21 , the sub-shell 12 is connected to the main shell 11 , and the sub-shell 12 and the main shell 11 are mutually on. Among them, the air knife device 15 , the electrostatic neutralization device 16 , the ultrasonic resonance device 17 , the flow control device 18 and the photomask protective film monitoring device 19 are arranged in the main casing 11 , and the conveying device 14 is arranged at a position across the The main casing 11 and the secondary casing 12 are assembled.

Please refer to FIG. 1B and FIGS. 2A and 2B again. FIG. 2A is a schematic diagram of the mask opening device 13 , and FIG. 2B is a schematic diagram of the cover opening element 132 rising. The mask opening device 13 includes a lifting element 131 and a cover opening element 132. The cover opening element 132 includes a back connecting portion 132B and a cover portion 132C. The back connecting portion 132B is connected to the cover portion 132C, and the cover The external appearance of the portion 132C is in the form of a U-shaped partition. It should be noted that the lifting element 131 is used to lift or lower the back connecting portion 132B and the cover portion 132C. In addition, the cover part 132C of the mask opening device 13 is embedded in the sub-casing 12 , and the cover part 132C and the back connecting part 132B form a mask entrance 132E, and the mask entrance 132E is where the mask box 8 is located. Placement area.

Please refer to FIGS. 3A and 3B , FIG. 3A is a schematic diagram of the transport device 14 , and FIG. 3B is a schematic diagram of the photomask box 8 embedded in the photomask inlet 132E. The transport device 14 includes a slide rail 141 and a photomask pod loading platform 142 , one end of the slide rail 141 is in the main casing 11 , the other end of the slide rail 141 is in the secondary casing 12 , and the photomask cartridge is loaded The stage 142 includes a rotary unit 142S, which is a rotary switch 82S corresponding to the chassis 82 . Specifically, when the rotary unit 142S turns the rotary switch 82S open, the tenon 82T is retracted into the chassis 82 , and is not embedded in the corresponding tenon seat 81T. In this way, the upper cover 81 and the bottom plate 82 of the photomask box 8 can be separated.

In addition, since the pod mounting table 142 is movably connected to the slide rail 141 , the mask cassette mounting table 142 can be moved to the mask entrance 132E through the slide rail 141 . Specifically, when the pod mounting platform 142 is moved into the sub-casing 12 via the slide rails 141 , the reticle pod mounting platform 142 is exposed at the mask entrance 132E (refer to FIG. 1B ). In this way, the mask cassette 8 can be set on the mask cassette mounting platform 142 (the mask cassette 8 is mounted on the mask cassette mounting platform 142 through the chassis 82).

Please refer to FIG. 3C . FIG. 3C is a schematic diagram of the cover opening element 132 opening the upper cover 81 . When the reticle box 8 is placed on the reticle box mounting platform 142 , the upper cover 81 of the reticle box 8 is abutted against the cover. on the cover portion 132C. Therefore, when the mask cleaning apparatus 10 wants to expose the mask 83 from the mask box 8, the rotary unit 142S will turn the rotary switch 82S and the lifting element 131 will immediately rise to the back connecting portion 132B, and the upper cover 81 will follow the cover portion. 132C rises upwards. After that, the upper cover 81 is separated from the chassis 82, and the photomask pod loading platform 142 at this moment only supports the chassis 82 and the photomask 83 above the chassis 82 (please refer to FIG. 3D).

Please refer to FIG. 3C and FIG. 4 again. FIG. 4 is a schematic diagram illustrating the movement of the chassis 82 and the mask 83 into the main casing 11 . It is worth noting that, after the lifting element 131 ascends the back connecting portion 132B, the transport device 14 will also move the chassis 82 and the photomask 83 into the main housing 11 via the photomask box mounting platform 142 , that is, the photomask 83 Move to below the air knife device 15 , the electrostatic neutralization device 16 and the ultrasonic resonance device 17 . Moreover, when the upper cover 81 and the cover portion 132C of the photomask box 8 are lifted upward, the upper cover 81 , the cover portion 132C, the main casing 11 and the sub-casing 12 form a closed space. In this way, the mask cleaning apparatus 10 can prevent external contamination particles from adhering to the mask protective film 83F during the process of taking out the mask 83 . In addition, when cleaning the photomask film 83F, the photomask film 83F can also be ensured in the closed space.

Please refer to FIG. 4 and FIG. 5 again. FIG. 5 is a schematic diagram of three sets of air knife devices 15 . The air knife device 15 includes an azimuth adjusting element 151 and an air knife nozzle 152 , and the air knife nozzle 152 is connected to the azimuth adjusting element 151 . The azimuth adjustment element 151 includes a first axis 151A, and the air knife nozzle 152 includes a second axis 152A, and the first axis 151A is perpendicular to the second axis 152A. Therefore, via the first axis 151A and the second axis 152A can move the air knife nozzle 152 up and down, left and right, and rotate, so as to adjust the height or the left and right position and rotation angle of the air knife device 15 .

In addition, the air knife device 15 is used to generate an air flow to the reticle film 83F, so as to blow the contamination particles away from the reticle film 83F by the air flow. Specifically, the air flow is sprayed from the air knife nozzle 152 , and the air knife nozzle 152 can change the spray angle of the air flow through the azimuth adjustment element 151 . Therefore, the air knife device 15 can be adjusted according to different thicknesses of the photomasks 83 (ie, the positions of the photomask protective films 83F), so as to achieve the best dust removal effect.

In addition, the mask cleaning apparatus 10 of the present embodiment has three sets of air knife devices 15, and the three sets of air knife devices 15 are arranged in a ㄇ shape. In this way, the two sets of lateral air-knife devices 15 have an excellent dust removal effect on the objects on the lateral facade.

In addition, each flow control device 18 corresponds to one air knife nozzle 152 , and the flow control device 18 is used to control the air flow rate entering the air knife nozzle 152 . In this way, it is beneficial for the air knife nozzle 152 to use the best airflow for dust removal, so as to achieve the best dust removal effect.

Please refer to FIG. 4 and FIG. 6 again. FIG. 6 is a schematic diagram of the electrostatic neutralization device 16 . The electrostatic neutralization device 16 includes an alpha ionizer 162 and a plurality of ion nozzles 161, and the alpha ionizer 162 is used to generate a plurality of alpha particles. Afterwards, the electrostatic neutralization device 16 produces a plurality of charged particles through the alpha particles, and these charged particles are then transferred to the mask film 83F through the ion nozzle 161 , so that the contamination particles are easily separated from the mask cover 83F. Among them, the electrostatic neutralization device 16 uses wind (clean gas) to quickly reach the charged particles to the surface of the photomask protective film 83F, so compared with the traditional electrostatic neutralization device, it can effectively remove static electricity.

Please refer to FIG. 4 and FIG. 7 again. FIG. 7 is a schematic diagram of the ultrasonic resonance device 17 . The ultrasonic resonance device 17 includes a height adjustment platform 171 and an ultrasonic vibration head 172 . The ultrasonic vibration head 172 is connected to the height adjustment platform 171 , and the height adjustment platform 171 is used to adjust the height position of the ultrasonic vibration head 172 . In the present embodiment, the ultrasonic resonance device 17 generates an ultrasonic wave to the photomask protective film 83F through the ultrasonic vibration head 172, so that the photomask protective film 83F and the contamination particles attached to the photomask protective film 83F are generated. son resonates. In this way, the contamination particles are easily dropped from the photomask film 83F to the outside. In the above, the frequency of the ultrasonic wave is not less than 20kHz, and the optimum frequency of the ultrasonic wave is about 35kHz.

In addition, the air knife device 15, the electrostatic neutralization device 16 and the ultrasonic resonance device 17 are all located above the photomask box mounting platform 142, so the air knife device 15, the electrostatic neutralization device 16 and the ultrasonic resonance device 17 can simultaneously The mask film 83F is dust-removed. In addition, by moving back and forth on the slide rail 141 through the photomask box mounting platform 142, the effect of cleaning the photomask protective film 83F can be further increased.

In addition, the reticle monitoring device 19 is provided on the side of the ultrasonic resonance device 17 . It should be noted that the reticle monitoring device 19 is used to monitor the amplitude of the reticle 83F. In this way, it is possible to prevent the photomask protective film 83F from vibrating too much due to ultrasonic vibration, which may cause damage to the photomask protective film 83F.

In addition, the air filter device 21 is disposed beside the flow control device 18 , and the air filter device 21 is used to filter the contamination particles, so as to reduce the contaminants in the mask cleaning apparatus 10 .

In this embodiment, when the reticle protective film 83F completes the cleaning process, the transport device 14 also returns the chassis 82 together with the reticle 83 to the reticle inlet 132E, that is, the opening of the reticle box 8 . Next, the mask opening device 13 combines the upper cover 81 with the chassis 82 , and the rotary unit 142S locks the rotary switch 82S, so that the mask 83 is stored in the mask box 8 again.

In conclusion, the reticle cleaning apparatus 10 has an excellent dust removal effect on the reticle protective film 83F via the air knife device 15 , the electrostatic neutralization device 16 and the ultrasonic resonance device 17 , and the reticle 83 is taken out and stored in the reticle. In the process of 83, it can also prevent external contamination particles from adhering to the photomask protective film 83F.

Please refer to FIG. 8 . FIG. 8 is a flowchart of the mask cleaning method of the present embodiment. The mask cleaning method of this embodiment is applied to the mask cleaning apparatus 10, and the mask cleaning method includes the following steps. First, referring to FIG. 1C , FIG. 3B and step S1 , place a mask box 8 to the mask inlet 132E. The mask box 8 includes an upper cover 81 and a chassis 82 , and a mask 83 is accommodated on the chassis 82 .

Then, referring to FIGS. 3C , 3D and step S2 , the upper cover 81 and the chassis 82 are separated, so that the reticle pod mounting platform 142 only supports the chassis 82 and the photomask 83 . Specifically, the upper cover 81 and the chassis 82 are opened and separated through the cover opening element 132 .

After that, referring to FIG. 4 and step S3 , the chassis 82 and the photomask 83 are moved into the main casing 11 via the transport device 14 .

After that, please refer to FIG. 6 and step S4. Step S4 is equivalent to an electrostatic neutralization step. A plurality of charged particles are produced by a plurality of α particles through the electrostatic neutralization device 16, and these charged particles are transmitted to the light through a clean gas. A mask 83F of the mask 83 is formed so that the contamination particles can be easily separated from the mask 83F of the mask.

After that, please refer to FIG. 7 and step S5, step 5 is equivalent to an ultrasonic resonance step, and an ultrasonic wave is generated to the photomask protective film 83F through the ultrasonic resonance device 17, so that the photomask protective film 83F and the photomask are attached to the photomask. The contamination particles on the protective film 83F resonate. Therefore, the contamination particles are easily dropped from the mask film 83F to the outside.

Afterwards, referring to FIG. 5 and step S6 , a plurality of air knife devices 15 generate an air flow to the photomask protective film 83F, so that the contamination particles are blown away from the photomask protective film 83F.

After that, referring to step S7 , the chassis 82 and the reticle 83 are returned to the reticle inlet 132E via the transport device 14 .

After that, referring to step S8 , the upper cover 81 and the chassis 82 are combined through the cover opening element 132 , so that the photomask 83 is accommodated in the photomask box 8 .

In the above-mentioned mask cleaning method, step S4, step S5 and step S6 are performed in sequence. However, in other embodiments, step S4 , step S5 and step S6 can also be performed simultaneously (please refer to FIG. 9 ). Specifically, the air knife device 15 , the electrostatic neutralization device 16 , and the ultrasonic resonance device 17 can simultaneously remove dust from the photomask protective film 83F, and do not need to be executed in sequence. In addition, in other embodiments, the pod mounting stage 142 can also be moved back and forth in the main casing 11 several times. In this way, it is equivalent that the above-mentioned steps S4 , S5 and S6 are performed repeatedly for many times, which is more conducive to cleaning the photomask protective film 83F.

To sum up, the mask cleaning method of this embodiment has an excellent dust removal effect on the mask protective film 83F by using the air knife device 15 , the electrostatic neutralization device 16 and the ultrasonic resonance device 17 of the mask cleaning apparatus 10 . In addition, in this method, the cleaned mask 83 is also stored in the original mask box 8 .

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the appended patent application.

10: Reticle cleaning equipment

11: Main shell

12: Secondary shell

132: Open cover element

132B: Back joint

132C: Cover part

14: Transporter

142: Reticle Cassette Mounting Stage

15: Air knife device

16: Static neutralization device

17: Ultrasonic resonance device

18: Flow control device

19:Reticle film monitoring device

81: upper cover

82: Chassis

83: Photomask

Claims (15)

A photomask cleaning device is applied to a photomask box, the photomask box includes an upper cover and a chassis, the chassis is provided with a photomask, the photomask has a photomask protective film, and the photomask cleaning device includes : a main casing; a primary casing, connected to the main casing; a mask opening device, provided with: a lifting element; the back connecting part; and a cover part embedded in the sub-casing, the cover part and the back connecting part form a mask entrance, and the upper cover abuts on the cover part; a conveying device provided with There are: a slide rail; and a photomask pod loading platform, which is moved to the photomask entrance via the sliding track, and the chassis is arranged on the photomask pod loading platform; and at least one air knife device for generating An airflow flows to the photomask protective film; wherein, when the lifting element lifts the back connecting portion and the cover portion, the upper cover, the cover portion, the main casing and the sub-casing form a closed space. The photomask cleaning apparatus of claim 1, wherein the air knife device comprises: an orientation adjustment element; and An air knife nozzle is connected to the azimuth adjusting element, and the azimuth adjusting element is used to adjust the angle of the air knife nozzle. The mask cleaning apparatus of claim 2, wherein the orientation adjustment element includes a first axis, the air knife nozzle includes a second axis, and the first axis is perpendicular to the second axis. The photomask cleaning apparatus according to claim 1 or 2, wherein the number of the air knife devices is plural, and the air knife devices are arranged in a ㄇ shape. The mask cleaning apparatus according to claim 1, further comprising an electrostatic neutralization device, the electrostatic neutralization device produces a plurality of charged particles with a plurality of alpha particles, and the charged particles are transmitted to the photomask through a clean gas protective film. The reticle cleaning apparatus of claim 1, wherein the chassis includes a rotary switch, and the reticle pod mount includes a rotary unit corresponding to the rotary switch. The reticle cleaning apparatus as claimed in claim 5, further comprising an ultrasonic resonance device for generating an ultrasonic wave to the reticle protective film. The mask cleaning apparatus according to claim 2, further comprising at least one flow control device for controlling the flow of air entering the air knife nozzle. The mask cleaning device according to claim 7, wherein the frequency of the ultrasonic wave is not less than 20 kHz. The mask cleaning apparatus of claim 7, wherein the ultrasonic resonance device comprises: a height adjustment platform; and an ultrasonic vibration head connected to the height adjustment platform. The reticle cleaning apparatus according to claim 7, further comprising a reticle film monitoring device for monitoring the amplitude of the reticle film. The mask cleaning apparatus according to claim 1, further comprising at least one air filter device for filtering the contamination particles in the main casing. A mask cleaning method, applied to the mask cleaning device as claimed in claim 7, the mask cleaning method comprising: placing a mask box on the mask entrance, the mask box comprising an upper cover and a chassis, and A photomask is accommodated on the chassis; the upper cover is separated from the chassis, so that the photomask box loading platform can only carry the chassis and the photomask; move the chassis and the photomask to the main housing generate an air flow to a reticle film of the reticle; return the chassis and the reticle to the reticle inlet; and combine the top cover with the chassis to accommodate the reticle to the reticle inside the box. The photomask cleaning method of claim 13, further comprising an electrostatic neutralization step, through which a plurality of alpha particles are used to produce a plurality of charged particles, and the charged particles are transmitted to the light through a clean gas cover film. The photomask cleaning method as claimed in claim 13, further comprising an ultrasonic resonance step, generating an ultrasonic wave to the photomask protective film through the ultrasonic resonance step.

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