JP2005221929A - Method for manufacturing photomask blank and method for manufacturing photomask - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a high-quality photomask blank having extremely little defect by easily and reliably removing a foreign matter or the like depositing on the surface of a light transmitting substrate (the principal surface and the end faces comprising side faces and chamfered faces). <P>SOLUTION: The method for manufacturing a photomask blank includes: cleaning the surface of a transparent substrate 1; and then forming a thin film as a transfer pattern to be transferred to a transfer material on the surface of the transparent substrate, wherein the surface of the transparent substrate is cleaned by carrying out surface improvement process to improve wettability of the surface of the transparent substrate by using, for example, a UV irradiation apparatus, and then the end faces of the surface of the transparent substrate are cleaned by using an end face cleaning apparatus, afterward the principal surface is subjected to at least one of scrub cleaning by using a cleaning tool, two-fluid spray cleaning by using a two-fluid spray nozzle 13, ultrasonic cleaning by using a ultrasonic cleaning nozzle 14, or the like. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a manufacturing method of a photomask for transfer used in photolithography and a manufacturing method of a photomask blank that is a material of the photomask, and more specifically, a high-density semiconductor integrated circuit such as LSI or VLSI, The present invention also relates to a method for manufacturing a photomask used for fine processing in a color filter for a CCD or LCD, and a method for manufacturing a photomask blank that is a material for the photomask.

In a conventional photomask blank manufacturing method, cleaning of a photomask glass substrate is performed as described in Patent Document 1, for example. That is, after the glass substrate is immersed and cleaned in a cleaning solution such as pure water, scrub cleaning of the side surface of the glass substrate and scrub cleaning of the main surface of the glass substrate are sequentially performed.
Japanese Patent Publication No. 3-29474

  However, since the glass substrate cleaning method described above is performed by immersing the glass substrate in a cleaning solution such as pure water before scrubbing the side surfaces, the foreign substances adhering to the side surface or chamfered surface of the glass substrate are washed with this cleaning solution. Or the like may wrap around the main surface of the glass substrate and the main surface may be contaminated by foreign matter or the like. If scrub cleaning is performed on the main surface of the glass substrate in this state, the load of scrub cleaning on the main surface increases, and foreign matter on the main surface may not be completely removed.

Furthermore, in the case of a glass substrate with low wettability, the cleaning liquid does not sufficiently wrap around the surface of the glass substrate, which may reduce the cleaning quality.
In particular, the foreign matter adhering to the side surface of the glass substrate or the end face of the chamfered surface is often an organic matter mainly generated during handling or an organic matter generated from the storage case contact portion. A thin film serving as a transfer pattern to be transferred to a transfer target formed on a glass substrate is formed extremely thin on the side surface of the glass substrate or the end face of the chamfered surface by wraparound during film formation by sputtering. The organic matter adhering to the end face has an adverse effect of reducing adhesion to an extremely thin film formed on the end face of the glass substrate, and may cause dusting contamination due to film peeling.

  The dust generation contamination due to this film peeling is that the surface roughness of the side surface of the glass substrate and the end face of the chamfered surface is larger than the surface roughness of the main surface of the glass substrate. Another cause is that it is difficult to completely remove adhered foreign substances. Moreover, since the foreign material adhering to the side surface or chamfered surface of the glass substrate goes around to the main surface in a later process, there is a possibility that the foreign material etc. on the surface of the glass substrate cannot be completely removed.

  The object of the present invention has been made in consideration of the above-mentioned circumstances, and easily and reliably removes foreign substances and the like adhering to the surface of the translucent substrate (the main surface, and the end surface composed of the side surface and the chamfered surface). Another object of the present invention is to provide a photomask blank manufacturing method capable of manufacturing a high-quality photomask blank with extremely few defects. Another object of the present invention is to provide a photomask manufacturing method capable of manufacturing a high-quality photomask with very few pattern defects caused by defects in the photomask blank.

  The method of manufacturing a photomask blank according to the first aspect of the present invention includes a thin film that becomes a transfer pattern for transferring onto a surface of a light-transmitting substrate after the surface of the light-transmitting substrate is cleaned. In the photomask blank manufacturing method for forming the transparent substrate, the surface of the light-transmitting substrate is cleaned by performing a surface modification treatment for improving the wettability of the surface of the light-transmitting substrate, and then the light-transmitting property. An end surface of the surface of the substrate is washed, and then a main surface of the surface of the translucent substrate is washed.

  A method for producing a photomask blank according to the invention described in claim 2 is the invention according to claim 1, wherein after the cleaning of the end surface of the light transmitting substrate, before the cleaning of the main surface of the light transmitting substrate, At least the main surface of the translucent substrate is etched using an etchant.

  According to a third aspect of the present invention, there is provided a photomask blank manufacturing method according to the second aspect of the invention, wherein the etching treatment is performed by bringing the etching solution into contact with the main surface of the light-transmitting substrate in a state of being stationary for a predetermined time. It is a paddle etching process.

  According to a fourth aspect of the present invention, there is provided a photomask blank manufacturing method according to any one of the first to third aspects, wherein the end face of the translucent substrate is cleaned by using a rotated cleaning tool. The scrub cleaning is performed by bringing the substrate into contact with the end face of the conductive substrate for cleaning.

  According to a fifth aspect of the present invention, there is provided a photomask blank manufacturing method according to any one of the first to fourth aspects, wherein the main surface of the translucent substrate is cleaned by using a rotated cleaning tool. Scrub cleaning for cleaning by contacting the main surface of the optical substrate, two-fluid jet cleaning for cleaning by jetting a cleaning liquid mixed with gas and solvent onto the main surface of the transparent substrate, and ultrasonic waves are applied. The cleaning liquid is at least one of ultrasonic cleaning that supplies the main surface of the light-transmitting substrate and performs cleaning.

  According to a sixth aspect of the present invention, there is provided a photomask blank manufacturing method according to any one of the first to fifth aspects, wherein the transparent substrate has a transparent surface before the surface modification treatment is performed on the surface of the transparent substrate. An end face polishing process is performed on the end face of the optical substrate.

  According to a seventh aspect of the present invention, there is provided a method of manufacturing a photomask, wherein the thin film in the photomask blank according to any one of the first to sixth aspects is patterned to form a transfer pattern on the surface of the light-transmitting substrate. It is characterized by this.

According to the first aspect of the present invention, before the end face of the translucent substrate is cleaned, a surface modification treatment for improving the surface of the translucent substrate including the end face is performed, and this translucency is achieved. Since organic substances attached to the surface of the substrate are decomposed and removed, and the wettability of the surface is improved, foreign matters attached to the end face of the translucent substrate can be easily and reliably removed. Can be prevented from wrapping around and adhering to the main surface of the translucent substrate. As a result, since the cleaning load on the main surface of the translucent substrate to be performed thereafter is reduced, foreign matters attached to the main surface can be reliably removed, and the surface of the translucent substrate (main surface and end surface). Sub-surface defects caused by foreign matters adhering to the film are extremely reduced, and a high-quality photomask blank can be manufactured.
In addition, since organic matter does not remain on the end face of the translucent substrate, even when an extremely thin film is formed on the end face of the translucent substrate by wraparound during film formation by sputtering, dust contamination due to film peeling occurs. do not do.
In addition, by cleaning the end face before cleaning the main surface, for example, even when the subsequent etching cleaning is a dipping type, it is possible to extremely reduce the wraparound of the end face to the main surface such as foreign matter.

  According to the second aspect of the present invention, at least the main surface of the translucent substrate is etched before cleaning the main surface of the translucent substrate. Foreign substances and the like attached to the main surface of the optical substrate can be effectively removed.

  In addition, since the end face of the translucent substrate is cleaned before the etching process of at least the main surface of the translucent substrate, the main surface is cleaned following the etching process of at least the main surface of the translucent substrate. Can be implemented. As a result, at least the main surface etching process and main surface cleaning of the translucent substrate can be repeatedly performed, so that the cleaning effect of the main surface of the translucent substrate can be remarkably improved.

  According to the third aspect of the present invention, since the paddle etching process is performed in which the etching solution is brought into contact with the main surface of the translucent substrate in a state of being stationary for a predetermined time, the usage amount of the etching solution can be further reduced. Further, the foreign substance and the like attached to the main surface of the translucent substrate can be more effectively removed by improving the etching action.

  In addition, cleaning of the end face of the translucent substrate is performed before the etching process of at least the main surface of the translucent substrate, and this etching process is performed in a state where the etching liquid is kept stationary for a predetermined time on the main surface of the translucent substrate. Since it is a paddle etching process to be contacted, this paddle etching process and the subsequent cleaning of the main surface of the translucent substrate can be performed continuously by the same apparatus. For this reason, compared with the case where the etching process of a translucent board | substrate and the main surface washing | cleaning of a translucent board | substrate are implemented with a separate apparatus, the washing | cleaning equipment of a translucent board | substrate can be simplified and cost can be reduced.

  According to the invention described in claim 4, since the cleaning of the end face of the translucent substrate is scrub cleaning in which a rotated cleaning tool is brought into contact with the end face of the translucent substrate for cleaning. In particular, it is possible to reliably remove foreign matters such as foreign matters firmly adhered to the end face of the substrate.

  According to the fifth aspect of the present invention, the cleaning of the main surface of the translucent substrate is at least one of scrub cleaning, two-fluid jet cleaning, and ultrasonic cleaning. Can be implemented. In particular, in the case of two-fluid jet cleaning or ultrasonic cleaning, the translucent substrate main surface through the cleaning tool that occurs when the main surface of the translucent substrate is cleaned using a brush or the like as a cleaning tool. Can be reliably prevented. In the case of scrub cleaning, it is possible to reliably remove foreign matters and the like that are firmly fixed to the main surface of the translucent substrate.

  According to the invention described in claim 6, since the end surface of the translucent substrate is subjected to end surface polishing before the surface modification treatment on the surface of the translucent substrate, the end surface of the translucent substrate is subjected to Adhering foreign matter can be suppressed as much as possible, and even when foreign matter or the like adheres to the end face, the foreign matter or the like can be easily removed by end face cleaning.

  According to the invention described in claim 7, since the photomask blank is manufactured using the photomask blank according to any one of claims 1 to 6, the photomask blank has a surface of a light-transmitting substrate. Since there are very few defects due to foreign matters adhering to the photomask, the photomask manufactured using this photomask blank has very few pattern defects due to the above defects, and a high-quality photomask can be obtained. it can.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a configuration diagram showing a spin cleaning apparatus used for cleaning a transparent substrate in an embodiment of a method for manufacturing a photomask blank according to the present invention. FIG. 2 is a configuration diagram showing another spin cleaning apparatus used for cleaning a transparent substrate in one embodiment of the method for manufacturing a photomask blank according to the present invention. FIG. 3 is a front view showing an ultraviolet irradiation device for modifying the surface of the transparent substrate in the embodiment of the photomask blank manufacturing method according to the present invention. FIG. 4 is a plan view showing an end face cleaning apparatus for cleaning the end face of the transparent substrate in one embodiment of the method for manufacturing a photomask blank according to the present invention. FIG. 5 is a configuration diagram showing a sputtering apparatus for forming a film on a transparent substrate cleaned by the spin cleaning apparatus of FIG. FIG. 6 is a partial side view showing a part of a transparent substrate which is a constituent element of the photomask blank.

  In the photomask blank manufacturing method in the present embodiment, for example, a surface modification process for improving the wettability of the surface of the transparent substrate 1 as a light-transmitting substrate is performed using an ultraviolet irradiation device 40 shown in FIG. Next, the end face of the transparent substrate 1 is cleaned using the end face cleaning apparatus 50 shown in FIG. 4, and then the main surface of the transparent substrate 1 is cleaned using the spin cleaning apparatus 10 of FIG. 1 or the spin cleaning apparatus 25 of FIG. Clean the surface. Following the cleaning of the main surface, the surface of the transparent substrate 1 is rinsed using the spin cleaning apparatus 10 or 25, and then the transparent substrate 1 is dried. Thereafter, a thin film serving as a transfer pattern to be transferred to the transfer target is formed on the main surface of the transparent substrate 1 by using the sputtering apparatus 30 shown in FIG. 5 to manufacture a photomask blank.

  Here, the surface of the transparent substrate 1 includes a main surface 2 on which a thin film serving as a transfer pattern to be transferred to a transfer object is formed, another main surface 2 located on the opposite side of the main surface 2, and these And a chamfered surface 5 formed between the main surface 2 and the side surface 4. Of these, the side surface 4 and the chamfered surfaces 5 on both sides of the side surface 4 are collectively referred to as an end surface 6.

The surface modification treatment of the transparent substrate 1 irradiates the transparent substrate 1 with ultraviolet rays to generate ozone around the transparent substrate 1, and removes organic substances adhering to the surface of the transparent substrate 1 by the oxidizing power of the ozone. There are ones in which ozone water is poured directly onto the surface of the transparent substrate 1 and organic substances adhering to the surface of the transparent substrate 1 are removed by the oxidizing power of ozone. In any case, the removal of the organic substance improves the wettability of the surface of the transparent substrate 1 and can easily and surely remove foreign matter adhering to the end surface 6 of the transparent substrate 1. And the like can be prevented from adhering to the main surface 2 of the transparent substrate 1. As a result, the cleaning load on the main surface 2 of the transparent substrate 1 to be performed thereafter is reduced, so that foreign matters adhering to the main surface 2 can be reliably removed, and the surface of the transparent substrate 1 (the main surface 2 and the end surface) can be removed. 6) Subsurface defects caused by foreign matter or the like adhering to 6) are extremely reduced, and a high-quality photomask blank can be manufactured.
In addition, since organic substances attached to the end surface 6 of the translucent substrate 1 are removed, even when an extremely thin film is formed on the end surface 6 of the translucent substrate 1 by wraparound during film formation by sputtering, the film is peeled off. Therefore, it is possible to prevent defects such as particles and to manufacture a high-quality photomask blank.

  The ultraviolet irradiation device 40 shown in FIG. 3 irradiates the transparent substrate 1 with ultraviolet rays to remove organic substances attached to the surface of the transparent substrate 1. This ultraviolet irradiation device 40 irradiates ultraviolet rays from both ultraviolet irradiation units 41 toward the transparent substrate 1 when the transparent substrate 1 is carried in between a pair of ultraviolet irradiation units 41 arranged at a predetermined distance. By exposing the transparent substrate 1 to an ozone atmosphere generated by ultraviolet irradiation, the surface of the transparent substrate 1 is modified by removing particularly organic substances attached to the surface of the transparent substrate 1 by the oxidizing power of ozone. Is. In FIG. 3, reference numeral 42 denotes a substrate holding unit that holds the transparent substrate 1.

When irradiating ultraviolet rays in the ultraviolet irradiation device 40, the shorter the wavelength, the more preferable the ultraviolet rays. Therefore, a low-pressure mercury lamp that irradiates ultraviolet rays with wavelengths of 185 nm and 254 nm is preferable, and an Xe ₂ excimer lamp that irradiates ultraviolet rays with a wavelength of 172 nm is more preferable. Further, in view of the point of oxidizing and scattering and removing organic substances whose molecular bonds are broken by ultraviolet energy during ultraviolet irradiation, it is preferable to perform this ultraviolet irradiation in an atmosphere containing oxygen (radical). The low-pressure mercury lamp or excimer lamp is installed in the ultraviolet irradiation unit 41.

  After the surface modification treatment of the transparent substrate 1 described above, the end surface 6 of the transparent substrate 1 is cleaned using the end surface cleaning apparatus 50 of FIG. The end surface cleaning apparatus 50 includes a pair of substrate holding units 51 disposed to face each other, and a pair of end surface cleaning units 52 disposed to face each other at positions 90 degrees away from the substrate holding units 51. It is configured. Each of the pair of substrate holding units 51 is configured such that each holding plate 53 can be moved forward and backward, and by moving these holding plates 53 forward, the opposite end surfaces 6 of the transparent substrate 1 are pressed, and the transparent substrate 1 is pressed. 1 is held in the chamber 54.

  The end surface cleaning unit 52 is provided with an end surface cleaning tool 57 such as a brush or a sponge via an arm 56 in the unit mechanical body 55, and the end surface cleaning tool 57 is rotationally driven. The unit mechanical body 55 allows the end surface cleaning tool 57 to advance and retreat with respect to the end surface 6 of the transparent substrate 1 that is not held by the holding plate 53 of the substrate holding unit 51, and slides the end surface cleaning tool 57 along the end surface 6. Configure as possible. Each of the pair of end surface cleaning units 52 rotates the end surface cleaning tool 57, the end surface cleaning tool 57 is held by the unit mechanical body 55 on the transparent substrate 1 that is not held by the holding plate 53 of the substrate holding unit 51. The end surface 6 of the transparent substrate 1 is scrubbed by being pressed against the end surface 6 and further moved (swinged) along the end surface 6. During this cleaning, a cleaning liquid is supplied between the end surface 6 of the transparent substrate 1 and the end surface cleaning tool 57.

  The end face 6 held by the holding plate 53 of the substrate holding unit 51 is rotated 90 degrees in the end face cleaning apparatus 50, and after the cleaned both end faces 6 are held by the holding plate 53 of the substrate holding unit 51, Cleaning is performed by the end surface cleaning tool 57 of the end surface cleaning unit 52. Alternatively, the end face 6 held by the holding plate 53 of the substrate holding unit 51 is another end face in which the arrangement positions of the substrate holding unit 51 and the end face cleaning unit 52 are shifted from the end face cleaning device 50 by 90 degrees. Cleaning is performed by the cleaning device 50 in the same manner as in the case of the end surface cleaning device 50.

  As described above, the cleaning of the end surface 6 of the transparent substrate 1 is scrub cleaning in which the rotated cleaning tool 57 is brought into contact with the end surface of the transparent substrate 1 to clean, so that the foreign matter firmly adhered to the end surface 6 of the transparent substrate 1 is used. In particular, organic foreign matters can be reliably removed.

  The cleaning of the end surface 6 of the transparent substrate 1 is not limited to the scrub cleaning in which the rotated cleaning tool 57 is brought into contact with the end surface 6 of the transparent substrate 1 as described above, and cleaning is performed by two-fluid jet cleaning or ultrasonic cleaning. There may be. In the two-fluid jet cleaning, a cleaning liquid in which a gas and a solvent are mixed is sprayed onto the end surface 6 of the transparent substrate 1 to clean the end surface 6. In the ultrasonic cleaning, a solvent as a cleaning liquid to which ultrasonic waves are applied is supplied to the end surface 6 of the transparent substrate 1 to clean the end surface 6.

  After cleaning the end face 6 of the transparent substrate 1 described above, the main surface 2 of the transparent substrate 1 is cleaned using the spin cleaning device 10 of FIG. 1 or the spin cleaning device 25 of FIG. Among these, the spin cleaning apparatus 10 shown in FIG. 1 is a single-wafer type, and includes a spin chuck 11 that holds the transparent substrate 1, a two-fluid jet nozzle 13 and an ultrasonic cleaning nozzle 14 that are provided in the arm 12, and an arm 21. And an etching nozzle 22 supported on the substrate.

  The spin chuck 11 is rotatably provided by an electric motor 17. The two-fluid injection nozzle 13 mixes the solvent supplied from the solvent supply device 18 via a solvent injection nozzle (not shown) and the gas supplied from the gas supply device 19 via a gas injection nozzle (not shown). Gas is jetted onto the main surface 2 of the transparent substrate 1 as a cleaning liquid. Further, the ultrasonic cleaning nozzle 14 applies ultrasonic waves to the solvent from the solvent supply device 18 and supplies this solvent to the main surface 2 of the transparent substrate 1 as a cleaning liquid. The two-fluid ejection nozzle 13 and the ultrasonic cleaning nozzle 14 are moved between the center of the main surface 2 of the transparent substrate 1 and the end surface 6 by the arm 12.

  The etching nozzle 22 supplies an etching solution supplied from the etching solution supply device 23, particularly for paddle etching (described later) onto the surface (at least the main surface 2) of the transparent substrate 1 held by the spin chuck 11. It is. Further, the periphery of the spin chuck 11 is covered with a cleaning cup 20 to prevent scattering of cleaning liquid or the like.

A spin cleaning device 25 shown in FIG. 2 is a device in which a cleaning tool 26 and a cleaning liquid supply nozzle 27 are installed in place of the two-fluid jet nozzle 13 and the ultrasonic cleaning nozzle 14 in the spin cleaning device 10. Therefore, in this spin cleaning device 25, the same parts as those of the spin cleaning device 10 are denoted by the same reference numerals and the description thereof is omitted.

  The cleaning tool 26 is a cup-type or cylindrical-type brush, sponge, or the like, and is rotationally driven in a direction opposite to the transparent substrate 1 held by the spin chuck 11 and rotated by the electric motor 17. The arm 12 that supports the cleaning tool 26 can press the cleaning tool 26 against the main surface 2 of the transparent substrate 1 held by the spin chuck 11, and the cleaning tool 26 can be applied to the main surface 2 of the transparent substrate 1. It is possible to move between the center and the end face 6. The cleaning liquid supply nozzle 27 supplies the solvent from the solvent supply device 18 to the surface of the transparent substrate 1 as a cleaning liquid.

The main surface 2 of the transparent substrate 1 is cleaned by at least one of scrub cleaning, two-fluid jet cleaning, ultrasonic cleaning, and immersion cleaning.
Scrub cleaning is performed by rotating the transparent substrate 1 by the electric motor 17 while supplying the cleaning liquid from the cleaning liquid supply nozzle 27 to the transparent substrate 1 in the spin cleaning apparatus 25 of FIG. The main surface 2 of the transparent substrate 1 is cleaned by being pressed and brought into contact with the main surface 2 of the transparent substrate 1 while rotating in the opposite direction.

  In the two-fluid jet cleaning, the gas from the gas supply device 19 and the solvent from the solvent supply device 18 are mixed in the spin cleaning device 10 of FIG. The main surface 2 is cleaned by spraying onto the main surface 2 of the substrate 1 and moving (swinging) the two-fluid injection nozzle 13 with respect to the transparent substrate 1 by the arm 12.

Further, in the ultrasonic cleaning, in the spin cleaning device 10 of FIG. 1, an ultrasonic wave is applied to the solvent from the solvent supply device 18 and the solvent to which the ultrasonic wave is applied is supplied to the main surface 2 of the transparent substrate 1 as a cleaning liquid. The main surface 2 is cleaned by moving (swinging) the ultrasonic cleaning nozzle 14 with respect to the transparent substrate 1 by the arm 12.
Further, in the immersion cleaning, ultrasonic waves are applied to a solvent as a cleaning liquid stored in an overflow tank (not shown), and the transparent substrate 1 is immersed and vibrated in the overflow tank, thereby causing the main surface 2 of the transparent substrate 1 to vibrate. It is to be washed.

  When the cleaning of the main surface 2 of the transparent substrate 1 is at least one of scrub cleaning, two-fluid jet cleaning, and ultrasonic cleaning, the single substrate cleaning of the transparent substrate 1 can be performed. In particular, in the case of two-fluid jet cleaning or ultrasonic cleaning, the main surface of the transparent substrate 1 through the cleaning tool that occurs when the main surface 2 of the transparent substrate 1 is cleaned using a brush or the like as a cleaning tool. Contamination of the surface 2 can be reliably prevented. Further, in the case of scrub cleaning, foreign matters and the like that are firmly fixed to the main surface 2 of the transparent substrate 1 can be reliably removed.

Examples of the solvent used for the scrub cleaning, the two-fluid jet cleaning, the ultrasonic cleaning or the immersion cleaning include ultrapure water, gas-dissolved water, acidic aqueous solution, alkaline aqueous solution, and surfactant. Of these, gas-dissolved water is preferable because it has a high ability to remove fine particles and prevents reattachment of foreign matters. The gas-dissolved water includes at least one selected from hydrogen gas-dissolved water, O ₂ gas-dissolved water, O ₃ gas-dissolved water, rare gas-dissolved water, and N ₂ gas-dissolved water.

  Also in the cleaning of the end surface 6 of the transparent substrate 1 by the end surface cleaning device 50, the solvent used when the main surface 2 of the transparent substrate 1 is cleaned by the spin cleaning device 10 or 25 is used as the cleaning liquid.

  The rinsing process and the drying process performed after cleaning the main surface 2 of the transparent substrate 1 as described above are performed using the spin cleaning apparatus 10 of FIG. 1 or the spin cleaning apparatus 25 of FIG. That is, the rinsing process is carried out from the rinse nozzle (not shown) to the surface of the transparent substrate 1 while rotating the transparent substrate 1 by the electric motor 17 while the transparent substrate 1 is held by the spin chuck 11 of the spin cleaning device 10 or 25. It is carried out by spraying a rinsing liquid such as pure water. Further, the drying process is performed by rotating the transparent substrate 1 by the electric motor 17 in a state where the transparent substrate 1 is held by the spin chuck 11 of the spin cleaning device 10 or 25.

  Further, after the cleaning of the end surface 6 of the transparent substrate 1 as described above and before the cleaning of the main surface 2 of the transparent substrate 1, the surface of the transparent substrate 1 (the main surface 2 and the end surface 6) is etched using an etching solution. At least the main surface 2 may be etched.

Examples of the etching solution used when etching the surface of the transparent substrate 1 described above include an alkaline aqueous solution containing NaOH, KOH, NH ₄ OH + H ₂ O ₂ or the like. The concentration of the alkaline aqueous solution is preferably 1 to 10%. If it is less than 1%, the etching ability is insufficient and the processing time increases, which is not preferable. If it exceeds 10%, the alkaline solution remains excessively, and the rinsing time increases, or This is not preferable because the substrate surface becomes rough. The concentration of the alkaline aqueous solution is more preferably 3 to 5%.

  Examples of the etching process using an alkaline aqueous solution include a dipping etching process, a jet etching process, or a paddle etching process in which an alkaline aqueous solution is brought into contact with the main surface 2 of the transparent substrate 1 in a stationary state for a predetermined time due to the surface tension. It is done. Among these, the paddle etching process is preferable in that it can prevent the reattachment of the foreign matter peeled from the main surface 2 of the transparent substrate 1 and can reduce the amount of the aqueous alkali solution used. This paddle etching process is performed in the spin cleaning apparatus 10 of FIG. 1 or the spin cleaning apparatus 25 of FIG. That is, the transparent substrate 1 is held on the spin chucks 11 of the spin cleaning apparatuses 10 and 25, and an alkaline aqueous solution as an etchant is supplied from the etching nozzle 22 to the transparent substrate 1 while the rotation of the spin chuck 11 is stopped. The paddle etching process is carried out.

  The processing time of this paddle etching process is appropriately selected depending on the concentration and temperature of the alkaline aqueous solution. In the jet etching process, the transparent substrate 1 is held on the spin chuck 11 of the spin cleaning apparatuses 10 and 25, and the alkaline aqueous solution as an etching solution is transparent from the etching nozzle 22 while the spin chuck 11 is rotated. This is performed by spraying on the substrate 1.

  As described above, since at least the main surface 2 of the transparent substrate 1 is etched before the main surface 2 of the transparent substrate 1 is cleaned, the main surface 2 of the transparent substrate 1 is formed by the etching process and the main surface cleaning. It is possible to effectively remove adhered foreign matters and the like.

  Further, since the end face 6 of the transparent substrate 1 is cleaned before the etching process of at least the main surface of the transparent substrate 1, the main surface 2 is cleaned following the etching process of at least the main surface 2 of the transparent substrate 1. Can be implemented. As a result, since the etching process and main surface cleaning of the main surface 2 of the transparent substrate 1 can be repeatedly performed, the cleaning effect of the main surface 2 of the transparent substrate 1 can be remarkably improved.

  Since the etching process is a paddle etching process in which an etching solution (for example, an alkaline aqueous solution) is brought into contact with the main surface 2 of the transparent substrate 1 for a predetermined time, the usage amount of the etching solution can be further reduced and the etching function can be reduced. The foreign matter adhering to the main surface 2 of the transparent substrate 1 can be removed more effectively.

  Further, since the end face 6 of the transparent substrate 1 is cleaned before the etching process of at least the main surface 2 of the transparent substrate 1 and this etching process is a paddle etching process, this paddle etching process and the subsequent transparent substrate are performed. 1 main surface cleaning can be continuously performed by the same apparatus (spin cleaning apparatus 10 or 25). For this reason, compared with the case where the etching process of the transparent substrate 1 and the main surface washing | cleaning of the transparent substrate 1 are implemented by a separate apparatus, the washing | cleaning equipment of the transparent substrate 1 can be simplified and cost can be reduced.

  By the way, in the said embodiment, the end surface 6 of the said transparent substrate 1 is edge-polished before implementation of the surface modification process of the transparent substrate 1. FIG. This is because foreign matter or the like is likely to adhere to the end surface 6 of the transparent substrate 1 and further it is difficult to remove the foreign matter or the like.

  As described above, since the end surface 6 of the transparent substrate 1 is subjected to the end surface polishing treatment before the surface modification treatment on the surface of the transparent substrate 1, foreign substances adhering to the end surface 6 of the transparent substrate 1 can be suppressed as much as possible. Even when foreign matter or the like adheres to the end face 6, the foreign matter can be easily removed by end face cleaning by the end face cleaning device 50.

  A thin film to be a transfer pattern is formed on the main surface 2 of the transparent substrate 1 etched and washed as described above, using the sputtering apparatus 30 of FIG. The sputtering apparatus 30 is a DC magnetron sputtering apparatus, and a magnetron cathode 32 and a substrate holder 33 are disposed inside a vacuum chamber 31. A sputtering target 35 is attached to a backing plate 34 in the magnetron cathode 32. The backing plate 34 is cooled directly or indirectly by a water cooling mechanism. The magnetron cathode 32, the backing plate 34, and the sputtering target 35 are electrically coupled. The transparent substrate 1 is held on the substrate holder 33.

  The vacuum chamber 31 is evacuated by a vacuum pump through the exhaust port 37. After the atmosphere in the vacuum chamber 31 reaches a degree of vacuum that does not affect the characteristics of the film to be formed, a mixed gas containing helium is introduced from the gas inlet 38 and a negative voltage is applied to the magnetron cathode 32 using the DC power source 39. In addition, sputtering is performed to form a thin film on the surface of the transparent substrate 1. The pressure inside the vacuum chamber 1 is measured by a pressure gauge 36.

The thin film formed on the main surface 2 of the transparent substrate 1 by the sputtering apparatus 30 is, for example, a light semi-transmissive film in a halftone phase shift mask blank or a light shielding film in a photomask blank. Here, the light semi-transmissive film in the halftone phase shift mask blank has a predetermined transmittance with respect to the exposure light, and one or more layers that shift the phase of the exposure light with respect to the transparent substrate 1 by a predetermined amount. It is the film | membrane comprised from.

  As the light semi-transmissive film, a single-layer structure light semi-transmissive film, or two or more low-transmittance layers and high-transmittance layers are laminated so that the phase angle and the transmittance become desired values. A designed light semi-transmissive film having a multilayer structure is included.

  As a light semi-transmissive film having a single layer structure, a material containing at least one of oxygen and nitrogen in metal and silicon (silicon), or a material containing at least one of carbon, fluorine and hydrogen, chromium oxide, fluoride Although chromium etc. are mentioned, what consists of at least one of metal, silicon, and nitrogen and oxygen is preferable. The metal here is one or more metals selected from titanium, vanadium, niobium, molybdenum, tantalum, and tungsten. A commonly used metal is molybdenum.

  As the light-transmitting film having a multilayer structure, the high-transmittance layer is substantially composed of silicon and at least one of nitrogen and oxygen, or metal (similar to the metal in the light-transmitting film having a single-layer structure described above) ), Silicon, and substantially consisting of at least one of nitrogen and oxygen. The low-transmittance layer is a metal film made of one or two or more alloys such as chromium, molybdenum, tantalum, titanium, tungsten, hafnium, and zirconium, or an oxide, nitride, or oxynitride of these metals or alloys. The thing using a thing, silicide, etc. is preferable.

As the light shielding film in the photomask, a light shielding film having a single layer or a multilayer structure made of chromium, a chromium compound containing oxygen, nitrogen, carbon, or the like in chromium, other chromium compounds, or the like can be given.

  Further, the sputtering pressure is preferably 0.20 to 0.40 pascal (Pa), more preferably 0.23 to 0.35 pascal, and most preferably 0.25 to 0.31 pascal. When the pressure of the sputtering atmosphere is low as in the above range, the density of the light semi-transmissive film can be improved and the film becomes dense.

  The thin film in the photomask blank (for example, halftone phase shift mask blank) manufactured as described above is patterned to form a transfer pattern on the surface of the transparent substrate 1, and the photomask (for example, halftone phase shift) Mask). In this case, since the photomask blank has very few defects due to foreign matters attached to the surface of the transparent substrate 1, the photomask manufactured using the photomask blank has a pattern due to the defects. Defects are extremely reduced, and a high-quality photomask can be obtained.

  For example, when manufacturing a halftone phase shift mask for ArF excimer laser, a resist film is formed on the light semi-transmissive film of the halftone phase shift mask blank for ArF excimer laser, and a resist pattern is formed by pattern exposure and development. To do. Next, the exposed portion of the light semi-transmissive film is removed by dry etching, and a pattern (hole, dot, etc.) is obtained on the light semi-transmissive film. After removing the resist, it is washed with sulfuric acid and rinsed with pure water or the like to produce a halftone phase shift mask for ArF excimer laser.

Hereinafter, the present invention will be described in more detail with reference to FIG. 7 using examples and comparative examples.
The surface modification treatment of the transparent substrate 1 in each example was performed by irradiating ultraviolet rays for 70 seconds using an Xe ₂ excimer UV lamp having a wavelength of 172 nm in the ultraviolet irradiation device 40 of FIG.

  Further, the end surface cleaning of the transparent substrate 1 in each example and comparative example is end surface scrub cleaning, and this end surface scrub cleaning is performed by rotating the end surface cleaning tool 57 (made of sponge) of the end surface cleaning apparatus 50 shown in FIG. 4 at 100 rpm. However, the end mechanical cleaning tool 57 was pressed against the end surface of the transparent substrate 1 by the unit mechanical body 55, and the end surface of the transparent substrate 1 was swung at a predetermined pace.

  The etching process of at least the main surface 2 of the transparent substrate 1 in each example and comparative example is a paddle etching process, and this paddle etching process is performed using the spin cleaning apparatus 10 of FIG. 1 or the spin cleaning apparatus 25 of FIG. An aqueous NaOH solution adjusted to 5% and 65 ° C. was dropped from the etching nozzle 22 onto the main surface 2 of the transparent substrate 1 and left standing for a predetermined time, and then rinsed with pure water.

  The main surface cleaning of the transparent substrate 1 in each example and comparative example is scrub cleaning, two-fluid jet cleaning, ultrasonic cleaning, and immersion cleaning. In scrub cleaning, a cleaning tool 26 (made of sponge) in the spin cleaning device 25 of FIG. 2 is pressed against the main surface 2 of the transparent substrate 1, and the transparent substrate 1 and the cleaning tool 26 are rotated in opposite directions at 50 rpm and 100 rpm, respectively. Carried out.

Further, in the two-fluid jet cleaning, in the spin cleaning device 10 of FIG. 1, N ₂ gas is supplied from the gas supply device 19 at a pressure of 0.4 MPa, and at the same time, 1.5 mg / liter of hydrogen gas is supplied from the solvent supply device 18. Dissolved ultrapure water was supplied and mixed at a predetermined flow rate, and this mixed fluid was sprayed from the two-fluid spray nozzle 13 onto the main surface 2 of the transparent substrate 1 as a cleaning liquid.

Ultrasonic cleaning is performed by using ultra-pure water (hydrogen gas-dissolved water) in which 1.5 mg / liter of hydrogen gas to which an ultrasonic wave having a frequency of 1.0 MHz is applied in the spin cleaning apparatus 10 of FIG. This was performed by supplying the main surface 2 of the transparent substrate 1 from the cleaning nozzle 14.
In both cases of the two-fluid jet cleaning and the ultrasonic cleaning, the two-fluid jet nozzle 13 and the ultrasonic cleaning nozzle 14 are swung between the center and the end surface of the main surface 2 of the transparent substrate 1, and one round trip is performed for 10 seconds. Run for 80 seconds at pace.

  Further, in immersion cleaning, ultrapure water as a solvent is stored in an overflow tank (not shown), and 1.0 MHz ultrasonic waves are applied to the ultrapure water. The transparent substrate 1 was immersed in ultrapure water in the overflow tank, and the transparent substrate 1 was swung.

  The rinsing process and the drying process in each example and comparative example were performed using the spin cleaning apparatus 10 of FIG. 1 or the spin cleaning apparatus 25 of FIG. The transparent substrate 1 is rinsed by rotating the transparent substrate 1 at a rotation speed of 300 rpm while holding the transparent substrate 1 on the spin chuck 11 of the spin cleaning device 10 or 25, and jetting ultrapure water from a rinse nozzle (not shown). It was carried out by letting. Further, the transparent substrate 1 was dried by rotating the transparent substrate 1 at a rotational speed of 1500 rpm while holding the transparent substrate 1 on the spin chuck 11 of the spin cleaning device 10 or 25.

  The immersion etching process in the comparative example is performed by immersing the transparent substrate 1 in a NaOH aqueous solution bath adjusted to a concentration of 5% and 65 ° C. for a predetermined time, and then placing the transparent substrate 1 in a ultrapure water bath adjusted to 50 ° C. It was carried out by immersing for a time and rinsing.

(Example 1)
The surface modification treatment was performed by irradiating the transparent substrate 1 with ultraviolet rays, and then end face scrub cleaning was performed on the end surface 6 of the transparent substrate 1, and then scrub cleaning was performed on the main surface 2 of the transparent substrate 1. Thereafter, the transparent substrate 1 was rinsed and dried. The end surface 6 of the transparent substrate 1 is subjected to end surface polishing and polished to a mirror surface.
When the number of foreign matters (size of 0.1 μm or more) on the surface of the transparent substrate 1 was measured with MAGICS manufactured by Lasertec, it was 956 before washing and 27 after washing, and the foreign matter removal rate was 97.2%. there were.

(Example 2)
The surface modification treatment is performed by irradiating the transparent substrate 1 with ultraviolet rays, then the end surface scrub cleaning is performed on the end surface 6 of the transparent substrate 1, and then the two-fluid jet cleaning is performed on the main surface 2 of the transparent substrate 1. After the implementation, the transparent substrate 1 was rinsed and dried. The end surface 6 of the transparent substrate 1 is subjected to end surface polishing and polished to a mirror surface.
When the number of foreign matters (size of 0.1 μm or more) on the surface of the transparent substrate 1 was measured with MAGICS manufactured by Lasertec, it was 1013 before cleaning and 13 after cleaning, and the foreign matter removal rate was 98.7%. there were.

(Example 3)
Surface modification treatment is performed by irradiating the transparent substrate 1 with ultraviolet rays, then end face scrub cleaning is performed on the end surface 6 of the transparent substrate 1, and then ultrasonic cleaning is performed on the main surface 2 of the transparent substrate 1. After that, the transparent substrate 1 was rinsed and dried. The end surface 6 of the transparent substrate 1 is subjected to end surface polishing and polished to a mirror surface.
When the number of foreign matters (size of 0.1 μm or more) on the surface of the transparent substrate 1 was measured by MAGICS manufactured by Lasertec, it was 798 before washing and 14 after washing, and the foreign matter removal rate was 98.2%. there were.

Example 4
The surface modification treatment is performed by irradiating the transparent substrate 1 with ultraviolet rays, then the end surface scrub cleaning is performed on the end surface 6 of the transparent substrate 1, and then the two-fluid jet cleaning is performed on the main surface 2 of the transparent substrate 1. After performing ultrasonic cleaning simultaneously, the transparent substrate 1 was rinsed and dried. The end surface 6 of the transparent substrate 1 is subjected to end surface polishing and polished to a mirror surface.
When the number of foreign matters (size of 0.1 μm or more) on the surface of the transparent substrate 1 was measured by MAGICS manufactured by Lasertec, it was 861 before washing and 8 after washing, and the foreign matter removal rate was 99.1%. there were.

(Example 5)
Surface modification treatment is performed by irradiating the transparent substrate 1 with ultraviolet rays, then end face scrub cleaning is performed on the end surface 6 of the transparent substrate 1, and then paddle etching is performed on the main surface 2 of the transparent substrate 1. After that, after scrub cleaning was performed on the main surface 2 of the transparent substrate 1, the transparent substrate 1 was rinsed and dried. The end surface 6 of the transparent substrate 1 is subjected to end surface polishing and polished to a mirror surface.
When the number of foreign matters (size of 0.1 μm or more) on the surface of the transparent substrate 1 was measured with MAGICS manufactured by Lasertec, it was 922 before cleaning and 16 after cleaning, and the foreign matter removal rate was 98.3%. there were.

(Example 6)
Surface modification treatment is performed by irradiating the transparent substrate 1 with ultraviolet rays, then end face scrub cleaning is performed on the end surface 6 of the transparent substrate 1, and then paddle etching is performed on the main surface 2 of the transparent substrate 1. After that, after performing two-fluid jet cleaning on the main surface 2 of the transparent substrate 1, the transparent substrate 1 was rinsed and dried. The end surface 6 of the transparent substrate 1 is subjected to end surface polishing and polished to a mirror surface.
When the number of foreign matters (size of 0.1 μm or more) on the surface of the transparent substrate 1 was measured with MAGICS manufactured by Lasertec, it was 973 before washing and 9 after washing, and the foreign matter removal rate was 99.1%. there were.

(Example 7)
Surface modification treatment is performed by irradiating the transparent substrate 1 with ultraviolet rays, then end face scrub cleaning is performed on the end surface 6 of the transparent substrate 1, and then paddle etching is performed on the main surface 2 of the transparent substrate 1. After that, the main surface 2 of the transparent substrate 1 was subjected to ultrasonic cleaning, and then the transparent substrate 1 was rinsed and dried. The end surface 6 of the transparent substrate 1 is subjected to end surface polishing and polished to a mirror surface.
When the number of foreign matters (size of 0.1 μm or more) on the surface of the transparent substrate 1 was measured by MAGICS manufactured by Lasertec, it was 1088 before washing and 4 after washing, and the foreign matter removal rate was 99.6%. there were.

(Example 8)
Surface modification treatment is performed by irradiating the transparent substrate 1 with ultraviolet rays, then end face scrub cleaning is performed on the end surface 6 of the transparent substrate 1, and then paddle etching is performed on the main surface 2 of the transparent substrate 1. After that, after performing two-fluid jet cleaning and ultrasonic cleaning on the main surface 2 of the transparent substrate 1 at the same time, the transparent substrate 1 was rinsed and dried. The end surface 6 of the transparent substrate 1 is subjected to end surface polishing and polished to a mirror surface.
When the number of foreign matters (size of 0.1 μm or more) on the surface of the transparent substrate 1 was measured by MAGICS manufactured by Lasertec, it was 801 before cleaning, 0 after cleaning, and the foreign matter removal rate was 100%. .

Example 9
Surface modification treatment is performed by irradiating the transparent substrate 1 with ultraviolet rays, then end face scrub cleaning is performed on the end surface 6 of the transparent substrate 1, and then paddle etching is performed on the main surface 2 of the transparent substrate 1. After that, after scrub cleaning was performed on the main surface 2 of the transparent substrate 1, the transparent substrate 1 was rinsed and dried. The end surface 6 of the transparent substrate 1 is subjected to end surface polishing and polished to a mirror surface.
When the number of foreign matters (size of 0.1 μm or more) on the surface of the transparent substrate 1 was measured with MAGICS manufactured by Lasertec, it was 729 before cleaning and two after cleaning, and the foreign matter removal rate was 99.7%. there were.

(Example 10)
Surface modification treatment is performed by irradiating the transparent substrate 1 with ultraviolet rays, then end face scrub cleaning is performed on the end surface 6 of the transparent substrate 1, and then paddle etching is performed on the main surface 2 of the transparent substrate 1. After that, after scrub cleaning was performed on the main surface 2 of the transparent substrate 1, the transparent substrate 1 was rinsed and dried. The end surface 6 of the transparent substrate 1 is subjected to end surface polishing and polished to a mirror surface.
When the number of foreign matters (size of 0.1 μm or more) on the surface of the transparent substrate 1 was measured with MAGICS manufactured by Lasertec, it was 939 before cleaning and 1 after cleaning, and the foreign matter removal rate was 99.9%. there were.

(Example 11)
Surface modification treatment is performed by irradiating the transparent substrate 1 with ultraviolet rays, then end face scrub cleaning is performed on the end surface 6 of the transparent substrate 1, and then paddle etching is performed on the main surface 2 of the transparent substrate 1. After that, after scrub cleaning was performed on the main surface 2 of the transparent substrate 1, the transparent substrate 1 was rinsed and dried. The end surface 6 of the transparent substrate 1 is subjected to end surface polishing and polished to a mirror surface.
When the number of foreign matters (size of 0.1 μm or more) on the surface of the transparent substrate 1 was measured with MAGICS manufactured by Lasertec, it was 842 before cleaning and three after cleaning, and the foreign matter removal rate was 99.6%. there were.

(Example 12)
Surface modification treatment is performed by irradiating the transparent substrate 1 with ultraviolet rays, then end face scrub cleaning is performed on the end surface 6 of the transparent substrate 1, and then paddle etching is performed on the main surface 2 of the transparent substrate 1. After that, after scrub cleaning was performed on the main surface 2 of the transparent substrate 1, the transparent substrate 1 was rinsed and dried. The end surface 6 of the transparent substrate 1 is subjected to end surface polishing and polished to a mirror surface.
When the number of foreign matters (size of 0.1 μm or more) on the surface of the transparent substrate 1 was measured by MAGICS manufactured by Lasertec, it was 868 before cleaning and 6 after cleaning, and the foreign matter removal rate was 99.3%. there were.

(Example 13)
The surface modification treatment was performed by irradiating the transparent substrate 1 with ultraviolet rays, then the end surface scrub cleaning was performed on the end surface 6 of the transparent substrate 1, and then immersion cleaning was performed on the main surface 2 of the transparent substrate 1. Thereafter, the transparent substrate 1 was rinsed and dried. The end surface 6 of the transparent substrate 1 is subjected to end surface polishing and polished to a mirror surface.
When the number of foreign matters (size of 0.1 μm or more) on the surface of the transparent substrate 1 was measured with MAGICS manufactured by Lasertec, it was 960 before washing and 25 after washing, and the foreign matter removal rate was 97.4%. there were.

(Comparative example)
The transparent substrate 1 is subjected to immersion etching processing, and then the end surface 6 of the transparent substrate 1 is subjected to end surface scrub cleaning, and then the main surface 2 of the transparent substrate 1 is subjected to scrub cleaning, and then the transparent substrate 1 is rinsed. And dried. The end surface 6 of the transparent substrate 1 is subjected to end surface polishing and polished to a mirror surface.
When the number of foreign matters (size of 0.1 μm or more) on the surface of the transparent substrate 1 was measured with MAGICS manufactured by Lasertec, it was 733 before cleaning, 156 after cleaning, and the foreign matter removal rate was 78.7. %Met.

The main surface 2 of the transparent substrate 1 processed as in Examples 1 to 13 is subjected to a single-layer light semi-transmission substantially composed of molybdenum, silicon, and nitrogen using the DC magnetron sputtering apparatus 30 shown in FIG. A film was formed to produce a halftone phase shift mask blank for ArF excimer laser (193 nm). In this case, Mo: Si = 10: 90 is used as the sputtering target 35, and a mixed gas of argon, nitrogen, and helium (gas flow rates: Ar = 10 sccm, N ₂ = 80 sccm, He = 40 sccm) is used as the sputtering gas. The pressure was set to 0.25 Pa, and the phase angle of the light semi-transmissive film was adjusted to approximately 180 ° to form a single-layer light semi-transmissive film substantially composed of molybdenum, silicon, and nitrogen.
Thereafter, heat treatment is performed at 250 ° C. for 30 minutes using a heat treatment apparatus, and a halftone phase shift for an ArF excimer laser (193 nm) having a single-layer light semi-transmissive film substantially composed of molybdenum, silicon, and nitrogen. A mask blank was manufactured.
The obtained halftone phase shift mask blank was stored in a storage case and conveyed to a mask production line. After conveyance, when the foreign matter on the surface of the halftone phase shift mask blank was confirmed by MAGICS manufactured by Lasertec, no foreign matter due to film peeling from the end face was confirmed.

A resist film (baking temperature: 190 ° C.) was formed on the light semi-transmissive film of the halftone phase shift mask blank, and a resist pattern was formed by pattern exposure and development. Next, the exposed portion of the light semi-transmissive film was removed by etching (dry etching with CF ₄ + O ₂ gas), and a pattern (hole, dot, etc.) was obtained on the light semi-transmissive film. After removing the resist, it was immersed in 98% sulfuric acid (H ₂ SO ₄ ) at 100 ° C. for 15 minutes, washed with sulfuric acid, and rinsed with pure water or the like to produce a phase shift mask for ArF excimer laser. No pattern defects were confirmed in the obtained phase shift mask.

It is a block diagram which shows the spin cleaning apparatus used in order to wash | clean a transparent substrate in one Embodiment in the manufacturing method of the photomask blank which concerns on this invention. It is a block diagram which shows the other spin cleaning apparatus used in order to wash | clean a transparent substrate in one Embodiment in the manufacturing method of the photomask blank which concerns on this invention. In one Embodiment in the manufacturing method of the photomask blank which concerns on this invention, it is a front view which shows the ultraviolet irradiation device for modifying the surface of a transparent substrate. In one Embodiment in the manufacturing method of the photomask blank which concerns on this invention, it is a top view which shows the end surface cleaning apparatus which cleans the end surface of a transparent substrate. It is a block diagram which shows the sputtering device which forms a film on the transparent substrate cleaned with the spin cleaning apparatus etc. of FIG. It is a partial side view which shows a part of transparent substrate which is a component of a photomask blank. It is a table | surface which shows the foreign material removal rate at the time of carrying out the surface modification process, the end surface cleaning process, the main surface cleaning process, etc. with a Example and a comparative example.

Explanation of symbols

1 Transparent substrate (translucent substrate)
2 Main surface of transparent substrate 6 End surface of transparent substrate 10 Spin cleaning device 13 2 Fluid jet nozzle 14 Ultrasonic cleaning nozzle 22 Etching nozzle 25 Spin cleaning device 26 Cleaning tool 40 Ultraviolet irradiation device 41 Ultraviolet irradiation unit 50 End surface cleaning device 57 End surface cleaning tool

Claims (7)

In the method for producing a photomask blank, after cleaning the surface of the light-transmitting substrate, forming a thin film to be a transfer pattern for transferring to the transfer object on the surface of the light-transmitting substrate.
The surface of the translucent substrate is cleaned by performing a surface modification process that improves the wettability of the surface of the translucent substrate, and then cleaning the end surface of the surface of the translucent substrate, Then, the main surface of the surface of the said translucent board | substrate is wash | cleaned, The manufacturing method of the photomask blank characterized by the above-mentioned.   The at least main surface of the translucent substrate is etched using an etchant after cleaning the end face of the translucent substrate and before cleaning the main surface of the translucent substrate. A method for producing a photomask blank according to 1.   3. The method of manufacturing a photomask blank according to claim 2, wherein the etching process is a paddle etching process in which an etching solution is brought into contact with a main surface of a light-transmitting substrate in a stationary state for a predetermined time.   4. The photo according to claim 1, wherein the cleaning of the end face of the translucent substrate is scrub cleaning in which a rotated cleaning tool is brought into contact with the end face of the translucent substrate for cleaning. Mask blank manufacturing method.   The main surface of the translucent substrate is cleaned by scrub cleaning in which a rotated cleaning tool is brought into contact with the main surface of the translucent substrate and cleaning liquid in which a gas and a solvent are mixed. It is at least one of two-fluid jet cleaning that performs cleaning by spraying on the surface, and ultrasonic cleaning that performs cleaning by supplying a cleaning liquid to which ultrasonic waves are applied to the main surface of the translucent substrate. The manufacturing method of the photomask blank in any one of Claim 1 thru | or 4.   6. The photomask blank according to claim 1, wherein an end surface of the translucent substrate is subjected to an end surface polishing treatment before the surface modification treatment on the surface of the translucent substrate. Method.   A method for producing a photomask, comprising: patterning a thin film in the photomask blank according to claim 1 to form a transfer pattern on a surface of a translucent substrate.

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