JP4859436B2 - Manufacturing method of glass substrate for mask blank, manufacturing method of mask blank, manufacturing method of mask for exposure, and manufacturing method of glass member for lithography - Google Patents

Description

  The present invention relates to a method for manufacturing a glass substrate for mask blank, which manufactures a glass substrate for mask blank after inspecting an internal defect of the glass substrate for mask blank, a method for manufacturing a mask blank using the glass substrate for mask blank, and the mask blank. The present invention relates to a method for manufacturing a mask for exposure using, and a method for manufacturing a glass member (lithographic glass member) as an optical component such as a lens used in a stepper used in lithography technology.

  In recent years, in response to miniaturization of semiconductor devices, the exposure light used in the photolithography technique has been shortened to ArF excimer laser (exposure wavelength 193 nm) and F2 excimer laser (exposure wavelength 157 nm). Even in an exposure mask used in the photolithography technique and a mask blank for manufacturing the exposure mask, light is blocked with respect to the exposure wavelength of the exposure light formed on the mask blank glass substrate. Development of a light-shielding film and a phase shift film for changing the phase has been rapidly carried out, and various film materials have been proposed.

Further, it is required that defects such as foreign matters and bubbles do not exist inside the mask blank glass substrate or the synthetic quartz glass substrate for manufacturing the mask blank glass substrate. In Patent Document 1, a He—Ne laser is incident on a glass substrate, and the internal defects are detected by detecting scattered light scattered by internal defects (foreign matter, bubbles, etc.) present on the glass substrate. A defect detection apparatus is disclosed.
Japanese Patent Application Laid-Open No. 8-261951

  However, an ArF excimer laser as exposure light is used even for an exposure mask manufactured from a synthetic quartz glass substrate or a mask blank glass substrate that has been determined to have no internal defects by the defect detection apparatus as described above. At the time of pattern transfer for transferring the mask pattern of the exposure mask to the semiconductor substrate, a transfer pattern defect due to the glass substrate described later may occur and transfer accuracy may be lowered.

  The cause is that scattering was not generated when a visible light laser such as a He-Ne laser was used as the exposure light. However, when high-energy light such as an ArF excimer laser or F2 excimer laser was used as the exposure light, This is probably because internal defects (local striae, contents, and foreign substances) that change the optical characteristics (for example, decrease the transmittance) exist in the glass substrate.

  Further, in the defect detection method and apparatus described in Patent Document 1, when the scattered light is detected by the CCD camera, if the surface state of each glass substrate that is an object to be inspected varies, the defect detection accuracy is ensured. There are cases where it is not possible.

  The object of the present invention has been made in consideration of the above-mentioned circumstances, and even when there is variation in the surface state of each synthetic quartz glass substrate which is an object to be inspected, A method for manufacturing a mask blank glass substrate that can easily and reliably detect internal defects that have a large effect on pattern transfer when short-wavelength light having a wavelength of 200 nm or less is used as exposure light, and manufacturing a mask blank from the mask blank glass substrate It is providing the manufacturing method of a mask blank, and the manufacturing method of the mask for exposure which manufactures the mask for exposure with favorable transcription | transfer precision from the said mask blank.

The manufacturing method of the glass substrate for mask blanks according to the first aspect of the present invention includes a preparation step of preparing a glass substrate having a surface including one end face for introducing a short wavelength light having a wavelength of 200 nm or less, and the preparation. and a detecting step of detecting an internal defect of a glass substrate, manufacturing a glass substrate for mask blank for manufacturing a glass substrate for a mask blank using the glass substrate that internal defects are not present to affect the pattern transfer in the detection step a method, said detecting step, the short-wavelength light having an energy that the internal defects of the glass substrate is deteriorated by introducing into the glass substrate, have a defect alteration step of alteration of the internal defects, the glass substrate is made of synthetic quartz, the short wavelength light, the energy per pulse is characterized by a 10 to 100 mJ / cm ² Is.

Method of manufacturing a glass substrate for a mask blank according to the invention of claim 2 is the invention according to claim 1, wherein the short wavelength light, in which the pulse width is characterized in that it is a 2～15Nse c is there.
According to a third aspect of the present invention, there is provided the mask blank glass substrate manufacturing method according to the first or second aspect, wherein the internal defect has a local optical characteristic with respect to an exposure light source having a wavelength of more than 200 nm. Characterized in that it is at least one of local striae, contents, or extraneous matter that is a defect in which local optical property changes occur with respect to an exposure light source having a wavelength of 200 nm or less. It is.

According to a fourth aspect of the present invention, there is provided the method for manufacturing a mask blank glass substrate according to any one of the first to third aspects, wherein the detecting step uses short wavelength light having a wavelength of 200 nm or less to the glass substrate. introduced at the same time as or the defective alteration process after the defect alteration step of alteration of the internal defects, by introducing a light in the visible region on the glass substrate, by detecting the light scattered by the altered the internal defects, the It has a defect specifying step for specifying an internal defect.

According to a fifth aspect of the present invention, there is provided a method for manufacturing a glass substrate for a mask blank according to the fourth aspect , wherein the introduction of visible light into the glass substrate in the defect identification step is performed on both of the glass substrates. It is characterized in that it is carried out under conditions that satisfy the total reflection condition between the main surface and the side surface.

The method for producing a mask blank glass substrate according to claim 6 is the glass according to any one of claims 1 to 5 , wherein in the detection step, short wavelength light having a wavelength of 200 nm or less is introduced. The substrate is characterized in that the main surface is in a state before being mirror-polished.

The manufacturing method of the mask blank which concerns on invention of Claim 7 is on the main surface of the glass substrate for mask blanks obtained by the manufacturing method of the glass substrate for mask blanks in any one of Claims 1 thru | or 6 . A mask blank is manufactured by forming a thin film to be a mask pattern.

A method for manufacturing an exposure mask according to an eighth aspect of the invention comprises patterning a thin film in the mask blank according to the seventh aspect , forming a mask pattern on the main surface of the glass substrate for mask blank, and for exposure. A mask is manufactured.

The method for producing a glass member for lithography according to the invention described in claim 9 includes a preparation step of preparing a glass material having an introduction surface for introducing short-wavelength light having a wavelength of 200 nm or less, and the inside of the prepared glass material. and a detection step of detecting a defect, a method for producing a lithographic glass member to produce a glass member for lithography using the glass material whose internal defect does not exist in the detection step, the detection step, the the short-wavelength light having an energy that the internal defects of the glass material is altered by introducing into the glass material, have a defect alteration step of alteration of the internal defects, the glass substrate is made of synthetic quartz, the short wavelength light are those energy per pulse is characterized by a 10 to 100 mJ / cm ^2.
The method for producing a glass member for lithography according to the invention described in claim 10 is characterized in that, in the invention described in claim 9, the short wavelength light has a pulse width of 2 to 15 nsec.
The method for producing a glass member for lithography according to the invention described in claim 11 is the invention according to claim 9 or 10, wherein the internal defect has a local optical characteristic with respect to an exposure light source having a wavelength of more than 200 nm. It is characterized by at least one of local striae, contents, and foreign substances that are defects in which no change occurs and local optical characteristics change with respect to an exposure light source having a wavelength of 200 nm or less. is there.

According to the invention described in any one of claims 1 to 3, in the detection step of detecting an internal defect of the glass substrate, short-wavelength light having a wavelength of 200 nm or less having energy that alters the internal defect is applied to the glass substrate. Since the internal defect is introduced into the material to alter the internal defect, the internal defect can be revealed by the alteration. As a result, even when there are variations in the surface state of individual glass substrates that are inspected objects, the internal defects (patterns when exposure is performed using short wavelength light having a wavelength of 200 nm or less as exposure light). It is possible to easily and reliably detect an internal defect that greatly affects the transfer.

According to the invention described in claim 4 , after introducing short wavelength light having a wavelength of 200 nm or less into the glass substrate and altering the internal defect of the glass substrate, or simultaneously modifying the internal defect, the glass The internal defect is specified by introducing light in the visible range into the substrate and detecting light scattered by the altered internal defect. From this, it is possible to easily detect internal defects in the glass substrate that cause transfer pattern defects that occur when pattern transfer is performed using short-wavelength light having a wavelength of 200 nm or less as an exposure wavelength by using visible light. be able to.

According to the invention described in claim 5 , since visible light is introduced into the glass substrate under the condition that satisfies the total reflection condition between the main surface and the side surface of the glass substrate, Can be confined in the glass substrate, so that a modified internal defect can be reliably detected without leakage.

According to the invention described in claim 6 , short wavelength light having a wavelength of 200 nm or less is introduced into the glass substrate in a state where the main surface is not mirror-polished, thereby altering and revealing internal defects of the glass substrate. Therefore, the main surface of only the glass substrate in which no internal defect is detected can be mirror-polished, and the waste of mirror-polishing the main surface of the glass substrate in which the internal defect is detected can be eliminated.

According to invention of Claim 7 or 8 , a mask blank is manufactured using the glass substrate for mask blanks obtained by the manufacturing method of the glass substrate for mask blanks in any one of Claims 1 thru | or 6 , An exposure mask is manufactured by patterning the thin film in the mask blank. Accordingly, when transferring the mask pattern of the exposure mask to the transfer object using the exposure mask, a glass substrate having no internal defects is used for the exposure mask. There is no region where the optical characteristics are locally changed (for example, the transmittance is reduced) due to the defect, the pattern transfer is not adversely affected and the transfer pattern defect does not occur, and the transfer accuracy can be improved. .

According to the invention of any one of claims 9 to 11, in the detection step of detecting an internal defect of the glass material, the short-wavelength light having a wavelength of 200 nm or less having energy that alters the internal defect is applied to the glass material. Since the internal defect is introduced into the material to alter the internal defect, the internal defect can be revealed by the alteration. As a result, even when there is a variation in the surface state of each glass material that is an object to be inspected, the internal defects (transmittance when a short wavelength light having a wavelength of 200 nm or less is used as a light source) exist in these glass materials. It is possible to easily and reliably detect an internal defect that has a large influence on a decrease or a temperature increase due to absorption of the short wavelength light.

  Hereinafter, the best mode of a method for manufacturing a mask blank glass substrate, a method for manufacturing a mask blank, and a method for manufacturing an exposure mask will be described with reference to the drawings. Hereinafter, the exposure light will be described as ArF excimer laser light (exposure wavelength: 193 nm) having an exposure wavelength of 200 nm or less.

[A] Method for Producing Mask Blank Glass Substrate From a synthetic quartz glass ingot produced by a production method described in JP-A-8-31723 and JP-A-2003-81654, about 152.4 mm × about 152. A synthetic quartz glass plate 1 (FIG. 1 (a)) obtained by cutting to 4 mm × about 6.35 mm is chamfered. Next, among the surfaces of the synthetic quartz glass plate 1, at least an end face 2 on the side where a short wavelength light having a wavelength of 200 nm or less (in this embodiment, light having an exposure wavelength (ArF excimer laser light)) is introduced; Then, the end surface 3 adjacent to the end surface 2 and receiving the scattered light 15 (FIG. 3) scattered by the internal defect 16 described later is mirror-polished to such an extent that the light having the exposure wavelength can be introduced, and then synthesized. A quartz glass substrate 4 is prepared (FIG. 1B).

  In this preparation step, the remaining end surfaces 18 and 19 of the surface of the synthetic quartz glass substrate 4 and the main surfaces 5 and 6 facing each other are not mirror-polished, and the surface roughness is about 0.5 μm. However, the surface roughness of the end faces 2 and 3 is about 0.03 μm or less.

  Next, a detection step of detecting whether or not the internal defect 16 exists in the synthetic quartz glass substrate 4 prepared in the above preparation step is performed. This detection process is performed after the defect alteration process for altering the internal defect 16 using the defect alteration apparatus 20 shown in FIG. 2, and after the defect alteration process, and is altered using the defect inspection apparatus 40 shown in FIG. And a defect identification step for identifying and detecting the internal defect 16.

  Here, among the internal defects 16 existing in the synthetic quartz glass substrate 4, there is no problem in the case of an exposure light source (for example, KrF excimer laser (wavelength: 248 nm)) having a wavelength of more than 200 nm. In particular, there are local striae, contents, and foreign substances as internal defects 16 which are problematic when the exposure light source has a wavelength of 200 nm or less. These internal defects 16 are produced by using the exposure mask 14 manufactured from the synthetic quartz glass substrate 4 through the mask blank glass substrate 7 and the mask blank 9 and the exposure light having a wavelength of 200 nm or less. Any pattern transfer that transfers the mask pattern of the mask 14 to the transfer object causes a local change in optical characteristics (for example, a decrease in transmittance), adversely affects the pattern transfer, and decreases the transfer accuracy. Become.

  The “local striae” is a region in which a metal element is mixed in the synthetic quartz glass as an impurity during the synthesis of the synthetic quartz glass. If the local striae are present in the mask blank glass substrate 7 of the exposure mask 14, a transmittance decrease of about 20 to 40% occurs at the time of pattern transfer, and transfer accuracy is lowered. In addition, the “content” is a region in which a metal element is mixed in the synthetic quartz glass as an impurity more than in the case of local striae. If the contents are present on the mask blank glass substrate 7 of the exposure mask 14, a transmittance decrease of about 40 to 60% occurs during pattern transfer. Furthermore, the “foreign matter” is an oxygen-excess region in which oxygen is excessively mixed in the synthetic quartz glass and does not recover after being irradiated with high-energy light. If the extraneous material is present on the mask blank glass substrate 7 of the exposure mask 14, the transmittance is reduced by about 5 to 15% during pattern transfer.

  As shown in FIG. 2, the defect alteration apparatus 20 that performs the defect alteration process includes the above-described internal defect 16 (local pattern transfer during pattern transfer) that exists in the synthetic quartz glass substrate 4 before the main surfaces 5 and 6 are mirror-polished. The local striae, contents, and foreign matters that cause a change in the optical characteristics are altered using the ArF excimer laser beam 25. That is, this defect alteration device 20 introduces ArF excimer laser light 25, which is light having an exposure wavelength as short-wavelength light (that is, light having the same wavelength as the exposure wavelength), from the end face 2 of the synthetic quartz glass substrate 4. The laser irradiation device 21 and the synthetic quartz glass substrate 4 are placed, and the synthetic quartz glass substrate 4 is respectively arranged in the X direction, the Y direction, and the Z direction with respect to the ArF excimer laser light 25 irradiated from the first laser irradiation device 21. And an XYZ stage 22 to be moved. While the XYZ stage 22 moves the synthetic quartz glass substrate 4 in the Y direction, the first laser irradiation device 21 emits ArF excimer laser light 25 in the Y direction (that is, the end surface) of the end face 2 of the synthetic quartz glass substrate 4. 2 in the longitudinal direction).

The ArF excimer laser beam 25 irradiated from the first laser irradiation device 21 has energy that alters the internal defect 16 of the synthetic quartz glass substrate 4, and specifically has a pulse width of 2 to 15 nsec, The energy per pulse is 10 to 100 mJ / cm ² . The pulse width of the ArF excimer laser beam 25 is preferably 12 nsec. The energy per pulse of the ArF excimer laser beam 25 is preferably 20 to 50 mJ / cm ² . If the energy per pulse of the ArF excimer laser beam 25 exceeds 100 mJ / cm ² , plasma is generated and the synthetic quartz glass substrate 4 is damaged, which is not preferable in terms of safety. Therefore, the ArF excimer laser beam 25 emitted from the first laser irradiation device 21 is scanned in the longitudinal direction of the end face 2 of the synthetic quartz glass substrate 4, so that the internal defect 16 exists in the synthetic quartz glass substrate 4. In this case, the internal defect 16 is altered and made apparent.

  As shown in FIG. 3, a defect inspection apparatus 40 that performs the defect identification step includes a second laser irradiation apparatus 42 that irradiates visible laser light 26 such as visible light, for example, He-Ne laser light, and the like. Mirrors 41A and 41B as optical path adjusting means for changing the optical path of the visible laser light emitted from the second laser irradiation device 42 and introducing it into a chamfered surface 49 (described later) of the end face 2 of the synthetic quartz glass substrate 4, and synthetic quartz An XYZ stage 43 for placing the glass substrate 4 and moving the synthetic quartz glass substrate 4 in the X direction, the Y direction, and the Z direction with respect to the visible laser light 26 irradiated from the second laser irradiation device 42, and the XYZ A CCD element and a lens for expanding the detection range of the CCD element (both shown) are installed on the end face 3 side of the synthetic quartz glass substrate 4 placed on the stage 43. And a CCD camera (line sensor camera) 45 having a detection visual field 44 over substantially the entire width direction of the synthetic quartz glass substrate 4 (that is, the longitudinal direction of the end face 3), and a USB cable 46 to the CCD camera 45 And a computer 47 connected by use.

  Here, as shown in FIG. 4, the end surfaces 2, 3, 18 and 19 of the synthetic quartz glass substrate 4 are the main surfaces of the synthetic quartz glass substrate 4 on which a thin film (halftone film 8 to be described later) serving as a mask pattern is formed. A side surface 48 orthogonal to the surfaces 5 and 6, and chamfered surfaces 49, 50 between the side surface 48 and the main surfaces 5, 6 are configured. In the present embodiment, the side surfaces 48 and the chamfered surfaces 49 and 50 of the end surfaces 2 and 3 are mirror-polished.

  As shown in FIG. 3, the mirrors 41 </ b> A and 41 </ b> B introduce the visible laser beam 26 irradiated from the second laser irradiation device 42 into one chamfered surface 49 of the end surface 2 of the synthetic quartz glass substrate 4. The introduced visible laser beam 26 satisfies the total reflection condition between the main surfaces 5 and 6 of the synthetic quartz glass substrate 4 and the side surfaces 48 of the end faces 2 and 18, that is, the total reflection is repeated and the inside of the synthetic quartz glass substrate 4 is repeated. The incident angle of the visible laser beam 26 to the chamfered surface 49 is adjusted so as to be confined to the chamfered surface. Specifically, the incident angle θi at which the visible laser light 26 introduced (incident) into the synthetic quartz glass substrate 4 from the chamfered surface 49 of the end face 2 hits the main surfaces 5 and 6 becomes larger than the critical angle θc and is visible. The mirrors 41A and 41B adjust the incident angle of the visible laser beam 26 on the chamfered surface 49 so that the incident angle (90 ° −θi) at which the laser beam 26 strikes the side surfaces 48 of the end surfaces 2 and 18 is larger than the critical angle θc. To do.

  The second laser irradiation device 42 and the mirrors 41A and 41B are configured so that the visible laser beam 26 is chamfered on the end face 2 of the synthetic quartz glass substrate 4 while the XYZ stage 43 moves the synthetic quartz glass substrate 4 in the Y direction. Are introduced sequentially from each position in the Y direction (that is, the longitudinal direction of the chamfered surface 49 of the end face 2). Therefore, the visible laser beam 26 is scanned in the longitudinal direction of the chamfered surface 49 at the end face 2 of the synthetic quartz glass substrate 4 and is introduced into the entire region of the synthetic quartz glass substrate 4. When the internal defect 16 exists in the synthetic quartz glass substrate 4 and this internal defect 16 has been altered by the defect alteration device 20, the visible laser beam 26 introduced into the synthetic quartz glass substrate 4 as described above. Are scattered by the altered internal defect 16 and emit scattered light 15.

  The CCD camera 45 converts the scattered light 15 obtained by scattering the visible laser light 26 incident on the chamfered surface 49 of the end surface 2 of the synthetic quartz glass substrate 4 in the Y direction from the internal defect 16 that has been altered into synthetic quartz. For each position of the glass substrate 4 in the Y direction, light is received from the end face 3 side of the synthetic quartz glass substrate 4 and photographed. In the present embodiment, the CCD camera 45 is a monochrome camera, and takes light and darkness of the scattered light 15 to photograph.

  The computer 47 inputs an image from the CCD camera 45 and processes the image for each position in the Y direction of the synthetic quartz glass substrate 4. The amount of light (intensity) of the scattered light 15 received by is analyzed with respect to the position of the synthetic quartz glass substrate 4 in the X direction. That is, when the light quantity of the scattered light 15 is greater than or equal to a predetermined threshold, the computer 47 determines that the altered internal defect 16 has scattered the scattered light 15 having a light quantity greater than or equal to the predetermined threshold. The position of is identified and detected.

  In the detection process using the defect alteration device 20 and the defect inspection device 40 described above, the main surfaces 5 and 6 of the synthetic quartz glass substrate 4 from which the internal defect 16 is not detected are mirror-polished so as to have a desired surface roughness. The glass substrate 7 for mask blank is obtained by carrying out precision grinding | polishing and cleaning process (FIG.1 (c)). The surface roughness of the main surfaces 5 and 6 at this time is preferably 0.2 nm or less in root mean square roughness (RMS).

[B] Mask Blank Manufacturing Method Next, a thin film (halftone film 8) to be a mask pattern is formed on the main surface 5 of the mask blank glass substrate 7 by a sputtering method, and a mask blank 9 (halftone phase) is formed. A shift mask blank) is produced (FIG. 1 (d)). The halftone film 8 is formed using a sputtering apparatus having the following configuration.

  This sputtering apparatus is a DC magnetron sputtering apparatus 30 as shown in FIG. 5 and has a vacuum chamber 31, and a magnetron cathode 32 and a substrate holder 33 are arranged inside the vacuum chamber 31. A sputtering target 35 bonded to a backing plate 34 is attached to the magnetron cathode 32. The backing plate 34 is directly or indirectly cooled by a water cooling mechanism. Further, the magnetron cathode 32, the backing plate 34, and the sputtering target 35 are electrically coupled. The glass substrate 7 is mounted on the substrate holder 33.

  The vacuum chamber 31 in FIG. 5 is exhausted by a vacuum pump through an 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 nitrogen is introduced from the gas introduction port 38, and a negative voltage is applied to the magnetron cathode 32 using the DC power supply 39. In addition, sputtering is performed. The DC power source 39 has an arc detection function and monitors the discharge state during sputtering. The internal pressure of the vacuum chamber 31 is measured by a pressure gauge 36.

[C] Manufacturing Method for Exposure Mask Next, as shown in FIG. 1, a resist is applied to the surface of the halftone film 8 of the mask blank 9 (halftone phase shift mask blank), followed by heat treatment. A resist film 10 is formed. (Figure 1 (e)).

  Next, a predetermined pattern is drawn and developed on the resist film 10 in the mask blank 11 with a resist film to form a resist pattern 12 (FIG. 1 (f)).

  Next, using the resist pattern 12 as a mask, the halftone film 8 is dry-etched to form a halftone film pattern 13 as a mask pattern (FIG. 1 (g)).

  Finally, the resist pattern 12 is removed to obtain an exposure mask 14 in which the halftone film pattern 13 is formed on the glass substrate 7 (FIG. 1 (h)).

[D] Manufacturing Method of Semiconductor Device The obtained exposure mask 14 is attached to an exposure apparatus, and the exposure mask 14 is used to form a semiconductor substrate (semiconductor wafer) by using an ArF excimer laser as exposure light and using a photolithographic technique. The mask pattern of the exposure mask is transferred to the resist film formed on the substrate, and a desired circuit pattern is formed on the semiconductor substrate to manufacture a semiconductor device.

[E] Effects of the Embodiments The configuration described above provides the following effects (1) to (5) according to the above embodiment.
(1) In the defect alteration step of the detection step for detecting the internal defect 16 of the synthetic quartz glass substrate 4, ArF excimer laser light having a wavelength of 200 nm or less and having energy for altering the internal defect 16 using the defect alteration device 26. Since 25 is introduced into the synthetic quartz glass substrate 4 to alter the internal defect 16, the internal defect 16 can be revealed by this alteration. As a result, even when the surface states of the individual synthetic quartz glass substrates 4 vary, internal defects existing in these synthetic quartz glass substrates 4 (the ArF excimer laser light 25 which is a short wavelength light having a wavelength of 200 nm or less) It is possible to easily and reliably detect an internal defect having a great influence on pattern transfer when exposure light is used.

  (2) In the defect identification step of the detection step, after the defect alteration step of introducing ArF excimer laser light 25 having a wavelength of 200 nm or less into the synthetic quartz glass substrate 4 and altering the internal defects 16 of the synthetic quartz glass substrate 4 Then, the visible laser beam 26 is introduced into the synthetic quartz glass substrate 4 by using the defect inspection apparatus 40, and the scattered light 15 scattered by the altered internal defect 16 is detected to identify the internal defect 16. From this, the visible laser beam 26 is used for the internal defect 16 of the synthetic quartz glass substrate 4 that causes a transfer pattern defect that occurs when pattern transfer is performed using a short wavelength light having a wavelength of 200 nm or less as an exposure wavelength. It can be easily detected.

  (3) In the defect identification step, visible laser light is applied to the synthetic quartz glass substrate 4 under conditions that satisfy the total reflection condition between the main surfaces 5 and 6 of the synthetic quartz glass substrate 4 and the side surfaces 48 of the end faces 2 and 3. 26 is introduced, the visible laser beam 26 can be confined in the synthetic quartz glass substrate 4, and the altered internal defect 16 can be reliably detected in the synthetic quartz glass substrate 4 without leakage. .

  (4) In the defect alteration process, ArF excimer laser light 25 having a wavelength of 200 nm or less is introduced into the synthetic quartz glass substrate 4 in a state before the main surfaces 5 and 6 are mirror-polished. Since the internal defect 16 is altered and becomes apparent, the main surfaces 5 and 6 of only the synthetic quartz glass substrate 4 in which the internal defect 16 is not detected can be mirror-polished, and the synthetic quartz glass substrate 4 in which the internal defect 16 is detected. The waste of mirror polishing the main surfaces 5 and 6 can be eliminated.

  (5) Glass substrate for mask blank using synthetic quartz glass substrate 4 in which internal defect 16 is not detected in the defect alteration step using defect alteration device 20 in the detection step and the defect identification step using defect inspection device 40 7 is manufactured, a mask blank 9 is manufactured using the mask blank glass substrate 7, and the exposure mask 14 is manufactured by patterning the halftone film 8 in the mask blank 9. Therefore, when the pattern is transferred to transfer the mask pattern 13 of the exposure mask onto the transfer object using the exposure mask 14 and the ArF excimer laser beam 25 having a wavelength of 200 nm or less, Since the synthetic quartz glass substrate 4 having no internal defect 16 is used, there is no region where the optical characteristics are locally changed (for example, the transmittance is reduced) due to the internal defect 16, and pattern transfer The transfer accuracy can be improved without adversely affecting the transfer pattern defects.

  As mentioned above, although this invention was demonstrated based on the said embodiment, this invention is not limited to this. For example, in the detection process in the above-described embodiment, the defect identifying process using the defect inspection apparatus 40 is performed after the defect modifying process using the defect modifying apparatus 20, but natural light is emitted after the defect modifying process. Alternatively, the altered internal defect 16 may be confirmed by visual observation using a condensing lamp. The defect may be detected by irradiating the glass substrate with light in the visible region or light from a condenser lamp simultaneously with the defect alteration step.

  In the defect identification step of the detection step in the above embodiment, the end surface 3 side on which the CCD camera 45 is disposed in the synthetic quartz glass substrate 4 is mirror-polished, but this mirror-polishing may not be performed. .

  Furthermore, the defect inspection apparatus 40 that performs the defect identification process of the detection process in the above embodiment has been described in which the CCD camera 45 is disposed on the end face 3 side of the synthetic quartz glass substrate 4. It may be arranged on the main surface 5 or 6 side of the glass substrate 4.

Moreover, in the defect alteration process using the defect alteration device 20 in the above embodiment, the case where ArF excimer laser light is used has been described, but the wavelength may be 200 nm or less, preferably light having a wavelength of 100 nm to 200 nm. An F2 excimer laser may be used. Alternatively, in order to obtain the same wavelength as an ArF excimer laser or F2 excimer laser, light from a light source such as a heavy water (D ₂ ) lamp may be dispersed to use the same center wavelength as ArF excimer laser or F2 excimer laser. Absent.

Moreover, although the said embodiment described what detects the internal defect 16 in the synthetic quartz glass substrate 4, synthetic quartz glass (synthetic quartz glass block) of the block state before cutting out this synthetic quartz glass substrate 4, or this The internal defect 16 existing in the synthetic quartz glass in the ingot state for producing the synthetic quartz glass block may be detected. In this case, at least the introduction surface for introducing the ArF excimer laser beam 25 having a wavelength of 200 nm or less needs to be mirror-polished. In the above embodiment, synthetic quartz glass is used as the material for the substrate. However, soda lime glass and multi-component glass materials such as SiO ₂ —TiO ₂ are also effective.

  Moreover, although the case of the halftone type phase shift mask blank which formed the halftone film | membrane on the glass substrate for mask blanks was described in the said embodiment, it is not limited to this. For example, a halftone phase shift mask blank having a halftone film on a synthetic quartz glass substrate 7 and a light shielding film on the halftone film, or a photomask having a light shielding film formed on the glass substrate 7 for mask blank It can be blank. A resist film may be formed on the light-shielding film of these halftone phase shift mask blanks and photomask blanks.

  Further, in the above embodiment, the mask blank glass substrate has been described as the lithography glass member, but it is also applied to a method of manufacturing an optical component (lithography glass member) such as a lens used in a stepper used in lithography technology. it can.

It is a manufacturing process figure which shows one Embodiment in the manufacturing method of the glass substrate for mask blanks which concerns on this invention, the manufacturing method of a mask blank, and the manufacturing method of the mask for exposure. The defect alteration apparatus used in the manufacturing method of the glass substrate for mask blanks concerning this invention is shown, (A) is a perspective view of the said apparatus, (B) is sectional drawing which shows the condition which changes the internal defect. It is a perspective view which shows the defect inspection apparatus used in the manufacturing method of the glass substrate for mask blanks which concerns on this invention. It is sectional drawing which shows the condition where an internal defect is specified and detected with the defect inspection apparatus of FIG. It is a schematic side view which shows the sputtering device used in the manufacturing process of the mask blank of FIG.

Explanation of symbols

1 synthetic quartz glass plate 2 end face (one end face)
3 End face 4 Synthetic quartz glass substrate 5, 6 Main surface 7 Mask blank glass substrate 8 Halftone film (thin film)
9 Mask blank 13 Halftone film pattern (mask pattern)
DESCRIPTION OF SYMBOLS 14 Exposure mask 15 Scattered light 16 Internal defect 20 Defect alteration apparatus 21 1st laser irradiation apparatus 25 ArF excimer laser beam (short wavelength light)
26 Visible laser beam 40 Defect inspection device 41A, 41B Mirror 42 Second laser irradiation device 45 CCD camera 48 Side surface 49, 50 Chamfered surface

Claims (11)

A preparation step of preparing a glass substrate having a surface including one end surface for introducing short-wavelength light having a wavelength of 200 nm or less;
A detection step of detecting an internal defect of the prepared glass substrate,
A method of manufacturing a glass substrate for a mask blank for manufacturing a glass substrate for a mask blank using the glass substrate that internal defects are not present to affect the pattern transfer in the detection step,
The detection step, the short-wavelength light having an energy that the internal defects of the glass substrate is deteriorated by introducing into the glass substrate, have a defect alteration step of alteration of the internal defects,
The glass substrate is made of synthetic quartz,
The short-wavelength light, a glass substrate manufacturing method for a mask blank, wherein the energy per pulse is 10 to 100 mJ / cm ^2. The short wavelength light, method of manufacturing a glass substrate for a mask blank according to claim 1, wherein the pulse width is 2~15nse c. The internal defect is a defect in which a local optical characteristic change does not occur with respect to an exposure light source having a wavelength of greater than 200 nm, and a local optical characteristic change occurs with respect to an exposure light source with a wavelength of 200 nm or less. The method for producing a glass substrate for a mask blank according to claim 1, wherein the glass blank substrate is at least one of a physics, a content, and a foreign material. The detection step is performed after the defect alteration step of introducing short wavelength light having a wavelength of 200 nm or less into the glass substrate to alter internal defects, or simultaneously with the defect alteration step.
By introducing a light in the visible region on the glass substrate, by detecting the light scattered by the altered the internal defects, of claims 1 to 3, characterized in that it has a defect specifying step of specifying the internal defects The manufacturing method of the glass substrate for mask blanks in any one . Introduction into the glass substrate light in the visible region in the defect specific process, according to claim 4, which comprises carrying out the total reflection condition is satisfied condition between the both main surfaces and side surfaces of the glass substrate A method for producing a mask blank glass substrate. The glass substrate in the detection step, the wavelength is introduced to the following short-wavelength light 200nm, the mask blank according to any one of claims 1 to 5 major surface characterized in that it is a state before being mirror-polished Method for manufacturing glass substrate. A mask blank is manufactured by forming a thin film to be a mask pattern on a main surface of a glass substrate for a mask blank obtained by the method for manufacturing a glass substrate for a mask blank according to any one of claims 1 to 6. A method for producing a mask blank. A method for producing an exposure mask, comprising: patterning a thin film in the mask blank according to claim 7 to form a mask pattern on a main surface of a glass substrate for mask blank to produce an exposure mask. A preparation step of preparing a glass material having an introduction surface for introducing short-wavelength light having a wavelength of 200 nm or less;
A detection step of detecting an internal defect of the prepared glass material,
A method of manufacturing a lithographic glass member to produce a glass member for lithography using the glass material whose internal defect does not exist in the detection step,
The detection step, the short-wavelength light having an energy that the internal defects of the glass material is altered by introducing into the glass material, have a defect alteration step of alteration of the internal defects,
The glass substrate is made of synthetic quartz,
The short wavelength light has an energy per pulse of 10 to 100 mJ / cm ² , and is a method for producing a glass member for lithography. The method for manufacturing a glass member for lithography according to claim 9, wherein the short wavelength light has a pulse width of 2 to 15 nsec. The internal defect is a defect in which a local optical characteristic change does not occur with respect to an exposure light source having a wavelength of greater than 200 nm, and a local optical characteristic change occurs with respect to an exposure light source with a wavelength of 200 nm or less. The method for producing a glass member for lithography according to claim 9 or 10, wherein the method is at least one of a reason, a content, and a foreign substance.

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