JP2010112980A - Cleaning method and cleaning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning method and cleaning device, simply and reliably removing deliquescent contaminant generated on a substrate. <P>SOLUTION: The cleaning device in accordance with one embodiment removes deliquescent contaminant 15 generated as contaminant on a mask substrate 11. The device includes: a cooling means 23 for controlling the relative humidity in the periphery of the contaminant 15 to the critical humidity of the contaminant or more and under 100% to make the contaminant into water drops; and a light source 22 for applying laser light to the contaminant 15 made into water drops. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cleaning method and a cleaning apparatus, and more particularly to a cleaning method and a cleaning apparatus that remove contaminants by irradiating light.

  When a photomask is used in a high energy exposure method using ArF excimer laser light or the like, it is known that ammonium sulfate crystalline foreign matters grow on the pattern surface of the mask as haze. At present, a mask having a haze is generally used after a pellicle provided for protecting a pattern surface is peeled off once to remove contaminants, and then the pellicle is newly attached. . Therefore, a simple cleaning method that can remove contaminants in a short time is expected.

  Conventionally, there has been proposed a laser cleaning method capable of cleaning by irradiating a contaminant on the mask pattern surface with laser light (Patent Document 1). Further, a steam laser cleaning method is known as one of laser cleaning methods (Non-Patent Document 1). In this method, after a liquid such as water is added to the surface of the substrate, the liquid is explosively evaporated by irradiation with laser light. In this method, the kinetic energy of the liquid molecules generated during the explosive evaporation is distributed to the contaminant, and the contaminant is removed from the substrate surface together with the liquid.

US Pat. No. 4,987,286 Andrew C. Tam et al. "Laser-cleaning Techniques for removal of surface particulates" J. Appl. Phys. 71 (7), pp3515-3523, 1 April, 1992

  As a liquid that explosively evaporates, Patent Document 1 describes capillary water, and Non-Patent Document 1 describes a liquid film applied to a substrate. However, since the capillary water existing in the gap between the substance and the substrate is not constant, the amount of water varies depending on the individual adhesion state and is extremely small. For this reason, the contaminant may not always be removed. Further, in order to newly apply a liquid onto the substrate, a liquid supply function is required, and the apparatus configuration is complicated.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a cleaning method and a cleaning apparatus that can easily and reliably remove contaminants.

  The cleaning method according to the first aspect of the present invention is a removal method for removing deliquescent pollutants generated as contaminants on a substrate, wherein the relative humidity around the contaminants is determined by the criticality of the contaminants. It has a step of controlling the humidity to be less than 100% and forming the contaminants into water droplets, and irradiating the water-contaminated contaminants with laser light. Thereby, a water droplet can be attached only to the area | region where the contaminant generate | occur | produced on the board | substrate, and a contaminant can be isolate | separated from a board | substrate simply and reliably.

  The cleaning method according to the second aspect of the present invention is the control method described above, wherein the relative humidity around the contaminant is controlled by lowering the temperature of the substrate. Thereby, the contaminant can be reliably made into water droplets, and the contaminant can be separated from the substrate.

  A cleaning method according to a third aspect of the present invention is the cleaning method described above, wherein the relative humidity around the contaminant is controlled by humidifying the periphery of the contaminant. Thereby, the contaminant can be reliably made into water droplets, and the contaminant can be separated from the substrate.

  A cleaning method according to a fourth aspect of the present invention is the above-described cleaning method, characterized in that humidification is performed using a saturated aqueous solution in which a solid substance having a critical humidity higher than the critical humidity of the contaminant coexists. To do. Thereby, the humidity around the pollutant can be easily controlled.

  A cleaning method according to a fifth aspect of the present invention is the above-described cleaning method, which is a saturated aqueous solution in which a solid substance having a critical humidity lower than the critical humidity of the contaminant coexists, and has a temperature higher than that of the substrate. It is characterized by humidifying using the saturated aqueous solution. Thereby, the humidity around the pollutant can be easily controlled.

  A cleaning method according to a sixth aspect of the present invention is the above-described cleaning method, wherein the substrate is a photomask substrate, a silicon substrate, a compound semiconductor substrate, an FPD manufacturing substrate, or a solar cell manufacturing substrate. Features.

  A cleaning method according to a seventh aspect of the present invention is the above-described cleaning method, wherein the substrate is a photomask substrate, and a pellicle is provided on a pattern surface of the photomask substrate, through the pellicle. Then, the laser beam is irradiated. Thereby, the contaminant can be easily separated from the substrate without removing the pellicle.

  A cleaning method according to an eighth aspect of the present invention is the above cleaning method, wherein the substrate is a photomask substrate, and a pellicle is provided on a pattern surface of the photomask substrate via a pellicle frame, By introducing a gas in equilibrium with the saturated aqueous solution into a space surrounded by a photomask substrate, the pellicle, and the pellicle frame, the humidity around the contaminant is controlled. As a result, the humidity around the contaminant can be controlled in a short time, and the time required for cleaning the substrate can be shortened.

  A cleaning method according to a ninth aspect of the present invention is the above cleaning method, wherein the substrate is a photomask substrate, and a pellicle is provided on a pattern surface of the photomask substrate via a pellicle frame, The absolute humidity in a space surrounded by the photomask substrate, the pellicle, and the pellicle frame is increased by leaving the photomask substrate with a pellicle in a clean room. Thereby, the absolute humidity of the space inside the pellicle can be easily increased.

  A cleaning method according to a tenth aspect of the present invention is the cleaning method described above, wherein the contaminant is ammonium sulfate.

  A cleaning apparatus according to an eleventh aspect of the present invention is a cleaning apparatus that removes deliquescent pollutants generated as contaminants on a substrate, wherein the relative humidity around the contaminants is determined as the criticality of the contaminants. It has a humidity control unit that controls the humidity to be less than 100% and converts the contaminants into water droplets, and a light source that irradiates the water-contaminated contaminants with laser light.

  A cleaning apparatus according to a twelfth aspect of the present invention is the above-described cleaning apparatus, wherein the humidity control unit controls the relative humidity around the contaminant by lowering the temperature of the substrate. It is what. Thereby, the contaminant can be reliably made into water droplets, and the contaminant can be separated from the substrate.

  A cleaning device according to a thirteenth aspect of the present invention is the above-described cleaning device, wherein the humidity control unit controls the relative humidity around the contaminant by humidifying the periphery of the contaminant. It is characterized by. Thereby, the contaminant can be reliably made into water droplets, and the contaminant can be separated from the substrate.

  A cleaning apparatus according to a fourteenth aspect of the present invention is the above-described cleaning apparatus, wherein the humidity controller uses a saturated aqueous solution in which a solid substance having a critical humidity higher than the critical humidity of the contaminant coexists. It is characterized by humidification. Thereby, the humidity around the pollutant can be easily controlled.

  A cleaning apparatus according to a fifteenth aspect of the present invention is the above-described cleaning apparatus, wherein the humidity control unit is a saturated aqueous solution in which a solid substance having a critical humidity lower than the critical humidity of the contaminant coexists, Humidification is performed using a saturated aqueous solution having a temperature higher than that of the substrate. Thereby, the humidity around the pollutant can be easily controlled.

  A cleaning apparatus according to a sixteenth aspect of the present invention is the above-described cleaning apparatus, wherein the substrate is a photomask substrate, a silicon substrate, a compound semiconductor substrate, an FPD manufacturing substrate, or a solar cell manufacturing substrate. Features.

  A cleaning apparatus according to a seventeenth aspect of the present invention is the above-described cleaning apparatus, wherein the substrate is a photomask substrate, and a pellicle is provided on a pattern surface of the photomask substrate. Then, the laser beam is irradiated. Thereby, the contaminant can be easily separated from the substrate without removing the pellicle.

  A cleaning apparatus according to an eighteenth aspect of the present invention is the above-described cleaning apparatus, wherein the substrate is a photomask substrate, and a pellicle is provided on a pattern surface of the photomask substrate via a pellicle frame, The humidity control unit controls the humidity around the contaminant by introducing a gas in equilibrium with the saturated aqueous solution into a space surrounded by the photomask substrate, the pellicle, and the pellicle frame. It is characterized by. As a result, the humidity around the contaminant can be controlled in a short time, and the time required for cleaning the substrate can be shortened.

  A cleaning device according to a nineteenth aspect of the present invention is the cleaning device described above, wherein the contaminant is ammonium sulfate.

  ADVANTAGE OF THE INVENTION According to this invention, the washing | cleaning method and washing | cleaning apparatus which can remove a contaminant easily and reliably can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. The following description shows preferred examples of the present invention, and the scope of the present invention is not limited to the following examples. In the following description, the same reference numerals denote the same contents.

  One of the causes of substrate contamination in a typical clean room is acid molecules such as sulfuric acid, nitric acid, hydrochloric acid, and hydrofluoric acid used in the manufacturing process, APM (ammonia perhydration), or HMDS (hexamethylene disilazane). By-products of treatment, basic ammonia molecules contained in the sweat of workers, reaction products of these with water vapor and carbon dioxide contained in the atmosphere, or their molecular clusters are inherently contaminated. It is known that this is a result of mixing as minute impurities in the clean room air that does not contain. While these are waiting for the next treatment in the manufacturing process or during processing, they adhere to the substrate and cause substrate haze.

  Conventionally, it has been common to provide a wet cleaning process at the stage where these contaminations are found, or in a manufacturing process in which contamination may occur. However, as a result of intensive studies, the present inventors have found that the chemical characteristics of the contaminants to be removed are deliquescent. There is no known cleaning method that positively utilizes this deliquescence. The present invention uses the deliquescence of contaminants to remove contaminants on the substrate surface by quasi-dry cleaning with a simple equipment structure compared to conventional wet cleaning methods.

Embodiment 1 FIG.
A cleaning apparatus according to Embodiment 1 will be described with reference to FIG. FIG. 1 is a diagram schematically showing a configuration of a cleaning apparatus 20 according to the present embodiment. Here, an example in which the mask substrate 11 constituting the mask 10 with the pellicle 13 is cleaned as the substrate to be cleaned will be described. The cleaning apparatus 20 according to the present embodiment performs a cleaning process for separating and removing the contaminant 15 attached to the pattern surface of the mask substrate 11.

  First, the configuration of the mask 10 to be cleaned is described. The mask 10 is a photomask used in an exposure process for a semiconductor or the like. The mask 10 includes a mask substrate 11, a pellicle frame 12, and a pellicle 13. A pattern 14 to be transferred at the time of exposure is formed on the mask substrate 11. This pattern 14 is formed on a transparent substrate such as quartz. The pattern 14 may be a halftone pattern or a phase shift pattern in addition to the light shielding pattern.

  A frame-shaped pellicle frame 12 is mounted on the pattern surface of the mask substrate 11. The pellicle frame 12 is attached so as to surround an area where the pattern 14 of the mask substrate 11 is formed. A pellicle 13 is provided on the side opposite to the pattern surface side of the pellicle frame 12. A pellicle 13 is mounted on the mask substrate 11 via the pellicle frame 12.

  Therefore, the space on the pattern surface is surrounded by the mask substrate 11, the pellicle frame 12, and the pellicle 13. Thereby, it is possible to prevent foreign matters flying from the outside from adhering to the pattern surface. A space surrounded by the mask substrate 11, the pellicle frame 12, and the pellicle 13 is defined as a pellicle space. The cleaning apparatus performs a cleaning process for separating and removing the contaminant 15 on the mask substrate 11 with the pellicle 13 mounted. Specifically, the contaminant 15 on the pattern surface is removed from the mask substrate 11 by irradiating laser light.

  The pollutant 15 has deliquescence. For example, ammonium sulfate. Such contaminants grow gradually by exposure light exposure or the like, and become foreign substances after a long time. The contaminant 15 includes not only a substance that can be optically detected as a foreign substance on the mask substrate 11 but also a minute substance that is difficult to optically detect.

  When such a minute contaminant 15 grows, exposure becomes a problem. Therefore, before the contaminant 15 grows to a size that causes a problem in exposure, the contaminant 15 is made into water droplets and irradiated with laser light to remove the contaminant 15 from the surface of the mask substrate 11. Alternatively, the contaminant 15 having a size that causes a problem in exposure is formed into water droplets, and the water droplets are irradiated with laser light to remove the contaminants 15 from the surface of the mask substrate 11. Thereby, it is possible to prevent the contaminant 15 from growing and causing a problem in exposure. Therefore, the lifetime of the mask 10 can be extended.

  Next, the configuration of the cleaning device 20 will be described. The cleaning apparatus includes a stage 21, a light source 22, and a cooling unit 23. The mask 10 is placed on the stage 21. The surface opposite to the pattern surface of the mask substrate 11 contacts the stage 21. The stage 21 is a hollow XY stage and supports the end of the mask substrate 11. When the stage 21 is driven, the mask 10 on the stage 21 moves in the horizontal direction. That is, the mask 10 moves with the stage 21 in the direction along the pattern surface. And the irradiation position of light can be aligned with the location where the contaminant 15 adhered.

  A light source 22 is provided above the mask 10. The light source 22 is preferably a light source for evaporating water explosively. That is, a light source that emits light of a wavelength having a high absorption coefficient for water or a high absorption coefficient for a substrate material is preferable.

  On the surface of the mask substrate 11 opposite to the pattern surface, cooling means 23 as a humidity control unit is provided. The cooling unit 23 controls the relative humidity around the contaminant 15 by cooling the mask substrate 11 and lowering the temperature of the mask substrate 11. As the cooling means 23, a cold plate, a liquid nitrogen nozzle, a vortex tube, or the like can be used.

  The cooling means 23 is disposed immediately below the location where the contaminant 15 is attached. The area where the contaminant 15 is present is partially cooled. As a result, the relative humidity around the pollutant 15 increases. The cooling means 23 keeps the relative humidity around the pollutant 15 at a critical humidity of the pollutant 15 or more and less than 100%.

  As described above, the pollutant 15 has deliquescence. A deliquescent material has the property of absorbing water vapor in an atmosphere of relative humidity above its critical vapor pressure. For example, when ammonium sulfate is generated as crystals on the mask substrate 11, if the atmosphere has a relative humidity of 81% or higher, which is the critical humidity of ammonium sulfate, the solid of the crystal absorbs water droplets of an aqueous ammonium sulfate solution that has absorbed water vapor due to deliquescence. Become.

  If the relative humidity around the contaminant 15 can be kept below 100%, that is, if the temperature of the mask substrate 11 is not lower than the dew point, water droplets are applied only to the portion where the deliquescent contaminant 15 exists on the surface of the mask substrate 11. Can be generated. The general storage environment of the mask 10 is 23 degrees, relative humidity 50%, absolute humidity 0.009 (kg / kg (DA) (DA: Dry Air)), and dew point 12.3 degrees.

  When the atmosphere in the pellicle space is the same as this storage environment, when the temperature of the mask substrate 11 is lowered to 15 degrees, the relative humidity near the substrate surface exceeds 81%, which is the critical humidity of ammonium sulfate, and deliquescence starts. As long as the temperature of the mask substrate 11 is not lowered to 12.3 degrees, the surface of the mask substrate 11 does not condense and water droplets can be formed only on the portion where the ammonium sulfate has adhered.

  In this way, in a humidity atmosphere in which the relative humidity around the pollutant 15 is equal to or higher than the critical humidity of the pollutant 15 and less than 100%, the pollutant 15 is deliquescent and becomes water droplets. As a result, on the mask substrate 11, water droplets in which the contaminant 15 is dissolved adhere only to the region where the contaminant 15 exists. Therefore, water droplets do not adhere to areas other than the areas where the contaminants are generated on the mask substrate 11.

  After the process of deliquescent the contaminant 15 is performed, a water droplet in which the contaminant 15 such as ammonium sulfate is dissolved is irradiated with a laser through the pellicle 13 to separate and remove the contaminant from the substrate surface.

  In the present invention, even if the scattered contaminant 15 is crystallized on the surface of the mask substrate 11, the size thereof is extremely small. That is, before the cleaning process is performed, the contaminant 15 that has been localized as a size causing a problem in exposure is widely dispersed on the surface of the mask substrate 11, the pellicle frame 12, the pellicle 13, and the like. For this reason, there is no fear of a mask defect, and there is no problem in the exposure process.

Embodiment 2. FIG.
A cleaning apparatus according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 2 is a diagram schematically showing the configuration of the cleaning apparatus 20 ′ according to the present embodiment. In the first embodiment, the example in which the temperature of the mask substrate 11 is lowered has been described as a method for controlling the relative humidity around the contaminant 15. In this embodiment, instead of this, an example in which the relative humidity around the contaminant 15 is controlled by humidifying the periphery of the contaminant 15 will be described. In FIG. 2, the same components as those in FIG.

  As shown in FIG. 2, the cleaning apparatus 20 ′ according to the present embodiment includes a stage 21, a light source 22, a supply unit 30, a supply pipe 31, an exhaust pipe 32, and an exhaust pump 33. Here, a supply port 16 and an exhaust port 17 are provided on the side wall of the pellicle frame 12. The supply port 16 and the exhaust port 17 penetrate the side wall of the pellicle frame 12. That is, the supply port 16 and the exhaust port 17 reach the pellicle space from outside the pellicle space.

  The pellicle space is a closed space except for the supply port 16 and the exhaust port 17. Gas is supplied from the supply port 16 into the pellicle space. Further, the gas in the pellicle space is exhausted from the exhaust port 17. The supply port 16 is provided with a joint, a fitting, and the like for connecting the supply pipe 31. Further, the exhaust port 17 is provided with a joint, a fitting, and the like for connecting the exhaust pipe 32. That is, each pipe is connected to the pellicle frame 12 by connection means such as a joint.

  A supply means 30 as a humidity control unit is connected to the supply pipe 31. The supply means 30 controls the relative humidity around the contaminant 15 by introducing a gas having a constant humidity into the pellicle space through the supply pipe 31 to humidify the periphery of the contaminant 15. As a result, the relative humidity around the pollutant 15 is kept above the critical humidity of the pollutant 15 and less than 100%, and the pollutant 15 is made into water droplets.

  As a method for obtaining a constant relative humidity stably with good reproducibility, a saturated aqueous solution of a salt compound known as a saturated salt method of a humidity standard can be used. The relative humidity of the sealed space on the saturated solution coexisting with the solid phase is stable and reproducible. Table 1 shows typical examples of substances and their relative humidity (%).

  Specifically, the supply means 30 can humidify using a saturated aqueous solution of a substance having a relative humidity higher than the critical humidity of the pollutant 15. When the pollutant 15 is ammonium sulfate, the critical humidity is 81%. Therefore, the relative humidity around the pollutant 15 can be controlled using a saturated aqueous solution of potassium chloride containing undissolved crystals having a higher relative humidity of 84%.

  Alternatively, a saturated aqueous solution of a substance having a relative humidity lower than the critical humidity of the contaminant 15 can be used, and humidification can be performed using a saturated aqueous solution having a temperature higher than that of the mask substrate 11. For example, when the temperature of the mask substrate 11 is 23 ° C., the relative humidity around the contaminant 15 can be set to 85% by using a saturated aqueous solution of sodium chloride containing undissolved crystals at 25 ° C. Thereby, it is possible to deliquefy ammonium sulfate which is the pollutant 15. At that time, if the relative humidity around the pollutant 15 can be kept below 100%, water droplets can be generated only in the portion where the deliquescent material exists on the surface of the mask substrate 11.

  In this way, by introducing the gas in equilibrium with the saturated aqueous solution into the pellicle space, the humidity around the pollutant 15 is controlled, so that the time required for forming the water droplet of the pollutant 15 can be shortened. . Even if the supply port 16 and the exhaust port 17 are not provided in the pellicle 13, the humidity in the pellicle space can be controlled by leaving the mask 10 in the space where the saturated aqueous solution providing the constant humidity exists. Is also possible.

  The absolute water vapor pressure in the pellicle space is almost zero, and in the first embodiment, it may be difficult to raise the relative humidity around the pollutant 15 to the critical humidity of the pollutant 15. In such a case, the necessary relative humidity can be realized by using the humidifying means of the second embodiment or the third embodiment described below.

  After the process of deliquescent the contaminant 15 is performed, a water droplet in which the contaminant 15 such as ammonium sulfate is dissolved is irradiated with a laser through the pellicle 13 to separate and remove the contaminant from the substrate surface.

  The exhaust pipe 32 is provided with an exhaust pump 33 that exhausts the gas in the pellicle space. As the exhaust pump 33, for example, a vacuum pump can be used. The exhaust pump 33 exhausts the gas in the pellicle space out of the pellicle space through the exhaust pipe 32. Thus, by sucking the contaminant 15 from the exhaust port 17, the contaminant 15 detached from the mask substrate 11 is discharged outside the pellicle space by the gas flow. As a result, the contaminant 15 can be prevented from growing and becoming a foreign substance, and the life of the mask 10 can be extended.

  In the present embodiment, the exhaust port 17 is formed on the side wall opposite to the side wall where the supply port 16 of the pellicle frame 12 is provided. That is, an exhaust port 17 is formed on one of two opposing sides of the frame-shaped pellicle frame 12, and a supply port 16 is formed on the other side. Therefore, when the supply by the supply means 30 and the exhaust by the exhaust pump 33 are performed, a gas flow is formed in the pellicle space in the direction along the pattern surface. Thereby, the gas in the pellicle space can be replaced.

  That is, the gas that has been present in the pellicle space from the beginning is exhausted, and the gas having a constant humidity supplied from the supply means 30 is filled in the pellicle space. Note that the exhaust port 17 and the supply port 16 are preferably provided at opposing positions. Further, it may be provided at a point-symmetrical position with respect to the center of the mask substrate 11 in the plane direction. Thereby, the pollutant 15 can be reliably removed irrespective of an adhesion location. Of course, a plurality of supply ports 16 and a plurality of exhaust ports 17 may be provided.

  In addition, by providing a filter or the like in the supply port 16, the exhaust port 17, the supply pipe 31, and the exhaust pipe 32, it is possible to prevent new foreign matters and contaminants from attaching. Further, a variable valve or the like for adjusting the amount of exhaust and supply air may be provided in the middle of the supply pipe 31 and the exhaust pipe 32. Further, in order to prevent the pellicle 13 from being excessively swollen or bent, the operation of the supply means 30 and the exhaust pump 33 may be controlled to control the exhaust amount and the supply amount.

Embodiment 3 FIG.
A cleaning apparatus according to Embodiment 3 of the present invention will be described below. In Embodiment 2, the supply means 30 for generating the humidification gas for humidification is required. The third embodiment is a method that does not require such a humidified gas generation means and simply realizes a desired relative humidity by utilizing the characteristics of the pellicle film.

  The film material of the pellicle 13 is an extremely thin fluoropolymer. The water vapor permeability of the fluoropolymer is approximately the same as that of high density polyethylene, and the pellicle 13 has effective water vapor permeability. The relative humidity of the clean room environment is usually 45%. By leaving the pellicle-equipped mask 10 stored in a dry air environment facility or the like in a clean room environment for a while, water vapor can be generated in the pellicle space that hardly contains water vapor without providing any special humidified gas generating means. Can be introduced. By cooling the mask substrate 11 after the introduction of the water vapor, the relative humidity in the vicinity of the contaminant 15 in the pellicle space can be controlled to a desired humidity. If the time for leaving the mask 10 in the clean room is acceptable, this is the simplest, most reliable and low cost cleaning method.

  The numerical values such as critical humidity described in the first, second, and third embodiments are suitable examples and are not particularly limited to the numerical values described. Moreover, you may use said Embodiment 1, 2, 3 combining suitably. Moreover, productivity can be improved by incorporating the above-described cleaning method into the production process. That is, the mask substrate 11 is manufactured by forming the pattern 14 on the transparent substrate. A pellicle 13 is mounted on the mask substrate 11 via a pellicle frame 12. And the process with respect to a contaminant is performed with respect to the mask 10 as mentioned above.

  When removing the contaminant 15, the portion of the mask substrate 11 where the contaminant 15 is attached is irradiated with light, and the contaminant 15 is detached from the mask substrate 11. Thereby, a contaminant can be removed reliably. Further, exposure is performed using the mask 10 from which the contaminant 15 has been removed. Thereby, exposure using the mask 10 from which the contaminant 15 has been reliably removed is performed. Therefore, productivity of patterned substrates such as semiconductors can be improved.

  As described above, according to the present invention, even if a mechanism for forming a water film on a substrate is not provided as in the prior art, a humidity control unit is provided to make use of the deliquescence of pollutants for contamination. Only the substance can be water-dropped. For this reason, the cleaning process can be performed easily and at low cost. In addition, since it has a simple structure in terms of equipment, it can be easily incorporated into existing manufacturing equipment such as transport equipment. Thus, the cleaning method according to the present invention is a cleaning method that can provide not only a means for reducing the cost of the cleaning apparatus but also a means for shortening the manufacturing time and a means for simplifying the manufacturing line.

  Note that the cleaning apparatus according to the present embodiment can also be used for a mask on which a pellicle is not mounted. Further, treatment may be performed on contaminants attached to a substrate other than the mask. For example, a silicon substrate, a compound semiconductor substrate, an FPD manufacturing substrate, and a solar cell manufacturing substrate can be cleaned. As a method of removing deliquescent pollutants such as the haze of the substrate, the relative humidity around the pollutants is kept above the critical humidity of the pollutants and less than 100%, and only the pollutants are deliquesced to form water droplets. Can do. Then, the laser beam is irradiated to the water droplet formed at the place where the contaminant is attached. Thereby, the process with respect to the contaminant on a board | substrate can be simplified.

It is a figure which shows typically the structure of the washing | cleaning apparatus which concerns on Embodiment 1. FIG. It is a figure which shows typically the structure of the washing | cleaning apparatus which concerns on Embodiment 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Mask 11 Mask substrate 12 Pellicle frame 13 Pellicle 14 Pattern 15 Contaminant 16 Supply port 17 Exhaust port 20 Cleaning device 21 Stage 22 Light source 23 Cooling means 30 Supply means 31 Supply pipe 32 Exhaust pipe 33 Exhaust pump

Claims (19)

A removal method for removing deliquescent pollutants generated as contaminants on a substrate,
Controlling the relative humidity around the pollutant to be not less than 100% of the critical humidity of the pollutant and forming the pollutant into water droplets;
Irradiating the water-contaminated contaminant with a laser beam;
A cleaning method comprising:   The cleaning method according to claim 1, wherein the relative humidity around the contaminant is controlled by lowering the temperature of the substrate.   The cleaning method according to claim 1, wherein the relative humidity around the contaminant is controlled by humidifying the periphery of the contaminant.   The cleaning method according to claim 3, wherein humidification is performed using a saturated aqueous solution in which a solid substance having a critical humidity higher than the critical humidity of the contaminant coexists.   4. The cleaning method according to claim 3, wherein the solid solution is a saturated aqueous solution in which a solid substance having a critical humidity lower than the critical humidity of the contaminant coexists, and humidification is performed using a saturated aqueous solution having a temperature higher than that of the substrate. .   The cleaning method according to claim 1, wherein the substrate is a photomask substrate, a silicon substrate, a compound semiconductor substrate, an FPD manufacturing substrate, or a solar cell manufacturing substrate. The substrate is a photomask substrate, a pellicle is provided on the pattern surface of the photomask substrate,
The cleaning method according to claim 1, wherein the laser beam is irradiated through the pellicle. The substrate is a photomask substrate, and a pellicle is provided on a pattern surface of the photomask substrate via a pellicle frame,
The humidity around the contaminant is controlled by introducing a gas in equilibrium with the saturated aqueous solution into a space surrounded by the photomask substrate, the pellicle, and the pellicle frame. Item 6. The cleaning method according to Item 4 or 5. The substrate is a photomask substrate, and a pellicle is provided on a pattern surface of the photomask substrate via a pellicle frame,
3. The absolute humidity in a space surrounded by the photomask substrate, the pellicle, and the pellicle frame is increased by leaving the photomask substrate with the pellicle in a clean room atmosphere. The cleaning method described.   The cleaning method according to claim 1, wherein the contaminant is ammonium sulfate. A cleaning device for removing deliquescent pollutants generated as contaminants on a substrate,
A humidity controller that controls the relative humidity around the pollutant to be equal to or higher than the critical humidity of the pollutant and less than 100%;
A light source for irradiating the water-contaminated contaminant with a laser beam;
Having a cleaning device.   The cleaning apparatus according to claim 11, wherein the humidity controller controls a relative humidity around the contaminant by lowering a temperature of the substrate.   The cleaning apparatus according to claim 11 or 12, wherein the humidity control unit controls the relative humidity around the contaminant by humidifying the periphery of the contaminant.   The cleaning apparatus according to claim 13, wherein the humidity control unit humidifies using a saturated aqueous solution in which a solid substance having a critical humidity higher than the critical humidity of the contaminant coexists.   The humidity controller is a saturated aqueous solution in which a solid substance having a critical humidity lower than the critical humidity of the contaminant coexists, and humidifies using a saturated aqueous solution having a temperature higher than that of the substrate. 13. The cleaning apparatus according to 13.   The cleaning apparatus according to claim 11, wherein the substrate is a photomask substrate, a silicon substrate, a compound semiconductor substrate, an FPD manufacturing substrate, or a solar cell manufacturing substrate. The substrate is a photomask substrate, a pellicle is provided on the pattern surface of the photomask substrate,
The cleaning apparatus according to claim 11, wherein the laser beam is irradiated through the pellicle. The substrate is a photomask substrate, and a pellicle is provided on a pattern surface of the photomask substrate via a pellicle frame,
The humidity control unit controls the humidity around the contaminant by introducing a gas in equilibrium with the saturated aqueous solution into a space surrounded by the photomask substrate, the pellicle, and the pellicle frame. The cleaning apparatus according to claim 14 or 15, wherein   The cleaning apparatus according to claim 11, wherein the contaminant is ammonium sulfate.

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