JP4100514B2 - Manufacturing method of glass substrate for electronic device, manufacturing method of photomask blank, and manufacturing method of photomask - Google Patents

Description

  The present invention is a glass substrate for electronic devices (particularly for photomasks and phase shift masks) capable of high-precision patterning, and a photomask blank (including a phase shift mask blank) and a photo using this glass substrate. The present invention relates to a mask (including a phase shift mask).

  In the manufacturing process of a semiconductor integrated circuit, a photomask, and the like, a photolithography method is used for forming a fine pattern. For example, when a semiconductor integrated circuit is manufactured, pattern transfer is performed using a photomask in which a pattern is formed by a light-shielding film (for example, a chromium film) on a transparent substrate that has been polished with high accuracy and is mirror-finished.

  In recent years, with increasing pattern density, severe demands have also been made for minute defects (foreign matter on the surface, scratches, striae, etc.) of the transparent substrate itself that has been polished and mirror-finished with high accuracy. As an inspection method for removing fine defects on the transparent substrate, there is JP-A-58-162038. In this method, light is collected in a very small area of the pattern surface, and the reflected and transmitted outputs from the pattern surface are compared to inspect the surface state of the substrate. However, in the above-described method, since only the reflected output and the transmitted output when the light is irradiated in a certain direction are compared and inspected, even with the latest inspection apparatus, a certain specific on the glass substrate surface. It was very difficult to reliably detect fine scratches with directionality, and defects such as striae in the glass substrate could not be inspected at all.

  This scratch having a specific direction is formed by a trajectory through which a foreign object passes due to the introduction of an undesirable foreign object during the polishing process of the glass substrate, or when the glass substrate is transported, It was formed when gripping the glass substrate after completion of polishing or after completion of polishing, and it was difficult to detect with a normal inspection method and inspection apparatus.

  In addition, when the size of a scratch having a specific direction on the surface of the glass substrate is expressed by the length in the major axis direction and the length in the minor axis direction perpendicular to the major axis direction, It was not possible to reliably detect a scratch whose length in the minor axis direction on the surface was 1 μm when the section was cut in a cross section perpendicular to the surface (although it is uncertain, the length in the minor axis direction was the smallest 0 The limit was to detect scratches of about 3 μm). In addition, the size of the concave portion existing on the main surface after this is expressed by “the length in the major axis direction and the length in the minor axis direction perpendicular to the major axis direction”, and each major axis direction. The length in the minor axis direction refers to the length on the main surface when the recess is cut in a cross section perpendicular to the main surface.

  Therefore, the present inventor has invented an inspection method and an inspection apparatus capable of inspecting nonuniformity of a light-transmitting substance such as a scratch on a glass substrate and striae (Japanese Patent Application No. 9-192863). In this inspection method, when the optical path of the translucent substance is optically uniform, light is introduced into the translucent substance so that total reflection occurs on the mirror-finished translucent substance substrate surface. When there is a non-uniform portion in the optical path of light introduced and propagated in the translucent substance, the light leaks from the surface, so that the non-uniformity of the translucent substance is detected. .

  According to the inspection method of the present invention, it is possible to reliably inspect non-uniformity such as scratches having a specific direction on the glass substrate surface that could not be reliably detected until now, and internal striae. became. In particular, as a scratch present on the surface of the glass substrate, not only can a scratch with a length of 1 μm in the minor axis direction be reliably detected, but also a non-uniformity inspection such as a striae present inside the glass substrate can be performed. It has become possible. Confirmation of such non-uniformity of the glass substrate has revealed the following problems and problems.

  FIG. 4 shows a case where a photomask is manufactured using a glass substrate having a concave portion (such as a scratch) 14 having a length of 1.2 μm in the minor axis direction defined above on the main surface of the glass substrate 11. Usually, a photomask is formed by forming a chromium film 12 having a light shielding function on a glass substrate 11 (FIG. 4A) (FIG. 4B) and further forming a resist film 13 (FIG. 4C). The resist film 13 is subjected to electron beam exposure and development to form a desired resist pattern 13 '(FIG. 4D). Next, using this resist pattern 13 ′ as a mask, wet etching is performed with, for example, an etchant obtained by adding pure water to ceric ammonium nitrate and peroxygen salt to form a chromium film pattern 12 ′ (FIG. 4 ( e)). This wet etching is usually over-etched in order to make the cross section of the chromium film pattern 12 'vertical, but at this time, it extends from the area where the chromium film pattern 12' is formed to the area where it is not formed. When the scratch 14 is present on the surface of the glass substrate 11, the etching solution penetrates the chromium film from the scratch 14, and there is a problem that a squeeze 15 as shown in FIG. This scratch of 1.2 μm in length is expected to have various adverse effects in addition to the problems described above.

  FIG. 5 shows a case where a phase shift mask (halftone mask) is manufactured using a glass substrate 21 having striae (defects having the same transmittance but different refractive index) 22 inside the glass substrate. In the phase shift mask, a molybdenum silicide nitride (MoSiN) film having a light shielding function and a phase shift function and a resist film are formed on the glass substrate 21 in FIG. 5A, and electron beam exposure and development are performed on the resist film. To form a desired resist pattern (not shown). Next, using this resist pattern as a mask, dry etching using, for example, a mixed gas of CF 4 and O 2 is performed to form a MoSiN film pattern 23 to produce a phase shift mask (FIG. 5B). When a pattern is transferred to a transfer object such as a semiconductor wafer using the obtained phase shift mask, the effect on the transfer object is influenced by the striae 22 inside the glass substrate 21 as shown in FIG. The light intensity distribution becomes an abnormal light intensity distribution 24 (25 is a normal light intensity distribution when there is no striae), and there is a problem that a desired pattern cannot be obtained.

  Further, a glass substrate inspected by a surface state inspection method described in, for example, Japanese Patent Application Laid-Open No. 58-162038, which collects light in a minute area on a conventional substrate surface and compares the reflected output and transmitted output for inspection. If the above photomask or phase shift mask is used to produce a photomask or phase shift mask as described above, it is desirable to transfer the pattern onto the transferred material as described above, even if a glass substrate that has been found to have no defects in the inspection is used. There was a problem that a simple pattern could not be obtained. This is because, in the case of a defect having a dependency on the traveling direction of the inspection light, such as a scratch on the substrate surface, since the scratch has a certain directionality, it may not be detected depending on the incident direction of the inspection light. This is because, in the case of defects such as striae inside the substrate, it is determined that there is no defect in the glass substrate because the reflected output is hardly detected by the conventional inspection method.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a glass substrate for an electronic device that enables high-precision patterning and projection exposure, and a photomask blank and a photomask using the same. And

  Note that the photomask blank and photomask referred to here include so-called ordinary photomask blanks and photomasks in which a light-shielding film (pattern) having a light-shielding function such as a chromium film or a MoSi film is formed on a transparent substrate. Of course, this includes a phase shift mask blank and a phase shift mask in which a phase shift film (pattern) having a light shielding function and a phase shift function, such as a MoSiN film or a MoSiON film, is formed on a transparent substrate.

  In order to achieve the above object, the present invention has the following structure.

The glass substrate for electronic devices of the present invention is
(Configuration 1) A glass substrate for an electronic device selected based on a certain reference setting value in a method for determining the presence or absence of a defect by optical change of inspection light, and the defect present on the glass substrate is the inspection light It is characterized in that it has no dependency on the direction of travel.

  In the case of a substrate that has been discriminated by comparing conventional reflected light and transmitted output by introducing inspection light in a certain direction, defects that depend on the traveling direction of the inspection light, such as scratches on the substrate surface, are reliably excluded. Can not do it. That is, the reflected output may not be detected at all because only light in a certain direction passes through the scratch. On the other hand, in the case of the non-uniformity inspection method for translucent substances described in Japanese Patent Application No. 9-192863 previously filed by the present inventor, light is irradiated from all directions toward the surface from the inside of the substrate. Therefore, even a defect having dependency on the traveling direction of the inspection light can be excluded. Therefore, the glass substrate for an electronic device of the present invention can be patterned with high accuracy without causing pattern defects in etching or the like at the time of patterning. Also, a photomask and a phase shift using this glass substrate. Appropriate exposure can be performed by the mask.

  Here, the optical change refers to a change in certain optical characteristics such as a change in the light amount and a change in the light traveling direction. The reference set value refers to light information (image information, light quantity, luminance, intensity distribution, etc.) obtained corresponding to an acceptable defect (non-uniformity) in the glass substrate for electronic devices. This is a threshold value to be set.

As an aspect of the configuration 1,
(Configuration 2) When the optical path of the glass substrate is optically uniform, the inspection light is obtained by introducing light into the glass substrate so that the total reflection repeatedly propagates on the surface of the glass substrate. It is characterized by this. That is, by introducing light that satisfies the total reflection condition into the glass substrate, when the optical path in the glass substrate is optically uniform, light from all directions fills the entire surface of the substrate and the entire interior of the substrate. Therefore, for example, even when there is a recess (scratch) with a specific direction on the glass substrate surface or when there is a defect such as striae inside the glass substrate, it is reliable and highly accurate, It becomes possible to detect the speed. Specifically, it is as defined in Configuration 8 to be described later.

As an aspect of the above configuration 2,
(Configuration 3) The inspection light is laser light, and the surface of the glass substrate has at least one set of main surfaces parallel to each other, at least one set of side surfaces orthogonal to the main surfaces, the main surfaces, and the side surfaces. And a chamfered surface rubbed by
When the optical path in the glass substrate is optically uniform, it propagates in the glass substrate, totally reflects on the main surface and the side surface, and repeats between at least one pair of side surfaces. Propagating and propagating the laser beam so that the laser beam spreads over the region to be inspected surrounded by the main surface, the side surface, and the chamfered surface.

  In this case, the introduced laser beam is likely to be substantially confined in the glass substrate by repeating total reflection on the main surface and side surfaces, and practically simultaneously inspecting a wide area of the glass substrate. This is preferable because high-speed inspection is possible. That is, the incident angle of light to the main surface where the introduced laser light repeats total reflection is the same, and the incident angle of light incident on the side surface is also the same, and they have a certain relationship (incident angle on the main surface). If θ is θ, the incident angle of the light incident on the side surface is 90 ° −θ), so that the incident angle on the main surface that first strikes after entering the glass substrate is larger than the critical angle. In addition, only by setting the incident angle to the side surface to be larger than the critical angle, optical confinement is substantially established. A specific method of introducing inspection light is as defined in Configuration 4.

As an aspect of Configuration 3,
(Configuration 4) The laser light is introduced from the chamfered surface, and when the optical path of the glass substrate is optically uniform, the laser light is introduced so as to be emitted only from the chamfered surface.

Moreover, the glass substrate for electronic devices of the present invention is
(Structure 5) A glass substrate for an electronic device, wherein the size of the concave portion present on the main surface on the side where the pattern of the glass substrate is formed is determined so that the length in the major axis direction is perpendicular to the major axis direction. The length in the minor axis direction on the main surface when the recess is cut in a cross section perpendicular to the main surface is 1 μm or less.

  Of the size of the recesses (surface defects such as scratches) on the main surface of the glass substrate for electronic devices, pattern defects occur in etching during patterning when the minor axis length is 1 μm or less. Therefore, high-precision patterning is possible, and appropriate exposure can be performed by a photomask and a phase shift mask using this glass substrate.

  The concave portion present on the surface of the glass substrate has a length in the minor axis direction of about 0.05 μm by a non-uniformity inspection method and inspection device for translucent substances described in Japanese Patent Application No. 9-192863. Even a concave portion having the same can be reliably detected.

As a preferable aspect of the configuration 5,
(Configuration 6) The length of the concave portion in the minor axis direction is 0.5 μm or less. When the thickness is 0.5 μm or less, generation of pattern defects is suppressed in etching or the like during patterning, and high-accuracy patterning is possible, and reliability is improved.

As a more preferable aspect of the configuration 5,
(Configuration 7) The length of the concave portion in the minor axis direction is 0.05 to 0.25 μm. If the length of the concave portion in the minor axis direction is less than 0.05 μm, the quality is of course good, but the yield deteriorates and the manufacturing cost increases, which is not preferable.

Moreover, the glass substrate for electronic devices of the present invention is
(Structure 8) A portion where optical characteristics with respect to transmitted light are not uniform does not substantially exist inside a glass substrate for electronic devices.

  A portion where the optical characteristics with respect to the transmitted light are not substantially non-existent within the glass substrate means that there are no non-uniform portions such as striae or bubbles, or a photomask or phase shift using this glass substrate. Even if exposure is performed using a mask, the light intensity distribution of the exposure light on the transferred material is merely a very small non-uniformity within a predetermined allowable range. Japanese Patent Application No. 9-192863 Any glass substrate in which non-uniformity such as striae is not detected by the described non-uniformity inspection method and inspection apparatus of the translucent substance is suitable without any problem.

As an aspect of the above configurations 5 to 7,
(Arrangement 9) The glass substrate for electronic devices is characterized in that there is substantially no portion having non-uniform optical characteristics with respect to transmitted light.

The photomask blank of the present invention is
(Structure 10) A thin film having at least a light shielding function is formed on the main surface of the glass substrate for electronic devices according to the structures 1 to 9.

The photomask of the present invention is
(Structure 11) A patterned thin film pattern having at least a light shielding function is formed on the main surface of the glass substrate for electronic devices according to structures 1 to 9.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A shows an embodiment of a photomask blank in which a chromium film is formed on a glass substrate for an electronic device according to the present invention, and FIG. 1B shows chromium on the glass substrate for an electronic device according to the present invention. It is typical sectional drawing which shows one Embodiment of the photomask in which the film | membrane pattern was formed, respectively.

  As shown to Fig.1 (a), the photomask blank consists of the glass substrate 1 and the chromium film | membrane 2 which has the light shielding function formed on the glass substrate 1. FIG. The glass substrate 1 is made of a quartz glass material having a size of 152.4 mm × 152.4 mm × 6.35 mm, whose main surface and side surfaces are precisely polished. The film thickness of the chromium film 2 is 1000 angstroms. The glass substrate 1 was confirmed to have no striae inside the glass substrate 1 by the inspection method of Japanese Patent Application No. 9-192863, and it was found that the surface of the glass substrate 1 was flawed. When the size of the scratch was confirmed with a microscope (AFM), it was confirmed that the length in the minor axis direction was not larger than 1 μm.

  Next, an example of the method for inspecting the non-uniformity of the translucent material of Japanese Patent Application No. 9-192863 will be briefly described with reference to FIG. FIG. 3 shows a non-uniformity inspection apparatus, in which the surface of the glass substrate 1 has a set of parallel main surfaces, two sets of side surfaces orthogonal to the main surfaces, and a chamfer sandwiched between the main surfaces and the side surfaces. The laser beam from the laser 4 is reflected by the mirrors 51 and 52, and is introduced into the glass substrate 1 from the chamfered side A (chamfered surface) of the glass substrate 1. The mirrors 51 and 52 are provided with an incident angle adjusting means 53 for adjusting the incident angle with respect to the glass substrate 1, and within a range where the laser beam causes total reflection on the surface (main surface and side surface) of the glass substrate 1. Incident light is incident upon varying the incident angle. Specifically, laser light is introduced from one side A of the chamfered glass substrate 1, and the introduced laser light repeats total reflection on the main surface and side surfaces (when the optical path of the glass substrate is optically uniform). It introduce | transduces in the glass substrate 1 so that a laser beam may radiate | emit from the chamfered one side A or the surface chamfered at the same angle as the one side A.

  The laser light incident on the glass substrate 1 repeats total reflection on the main surface and side surface of the glass substrate 1 and repeats through a different path or the same path between a pair of side surfaces, while one side B of the glass substrate 1 It propagates in a state where it is almost confined in a flat (thin plate) region along the line. This process is carried out by sequentially moving the laser 4, mirrors 51, 52, and the like together with the table 7 along the one side A of the glass substrate 1 by the driving device 6, and the laser light is propagated to all areas in the glass substrate 1. .

  If there is a non-uniform part such as a scratch on the surface of the glass substrate 1 or a non-uniform part such as a striae inside the glass substrate 1, the optical path (if the laser light is essentially uniform, where the scratch and refractive index are different) Path), the total reflection condition on the surface of the glass substrate 1 is not satisfied, and the laser light leaks from the main surface of the glass substrate 1. The leaked laser light is imaged on the CCD 9 by the lens system 8 and detected. As described above, since the total reflection which is a physical critical phenomenon is used, the response to the inspection light in the non-uniform portion and the uniform portion of the glass substrate 1 becomes critical, and the non-uniformity is very clear. And non-uniformities such as minute scratches can be detected with high sensitivity. Furthermore, not only nonuniformity of the surface of the glass substrate 1 but also defects such as internal striae can be detected.

  In the photomask shown in FIG. 1B, a resist film is formed on the photomask blank of FIG. 1A, and the resist film is subjected to electron beam exposure and development to form a desired resist pattern. Next, using this resist pattern as a mask, 165 g of ceric ammonium nitrate and 42 ml of a 70% concentration of peroxygen salt are added to pure water to maintain a 1000 ml etching solution at a temperature of 19 ° C. to 20 ° C. The chrome film pattern 2 ′ is formed by wet etching.

  Further, the phase shift mask blank shown in FIG. 2A has a glass substrate 1 and MoSiN (Mo: 13 at%, Si: 40 at%, N: 47 at%) having a light shielding function and a phase shift function, and a refractive index. Is 2.34, the light transmittance at a wavelength of 248 nm is 5%, and the phase shift amount is 180 °). The glass substrate 1 is made of a quartz glass material having a size of 152.4 mm × 152.4 mm × 6.35 mm, whose main surface and side surfaces are precisely polished. This glass substrate 1 was confirmed by the inspection method of FIG. 3 that there was no striae inside the glass substrate, and it was found that there were scratches on the surface of the glass substrate. When the size was confirmed by (AFM), it was confirmed that the scratch was 1 μm in length in the minor axis direction. The film thickness of the MoSiN halftone film 3 is 925 angstroms.

  In the phase shift mask of FIG. 2B, a resist film is formed on the phase shift mask blank of FIG. 2A, and the resist film is subjected to electron beam exposure and development to form a desired resist pattern. Then, using this resist pattern as a mask, a MoSiN film pattern 3 'is formed by dry etching using a mixed gas of CF4 and O2.

  In these photomasks and phase shift masks, the scratches that were just found existed over the area formed from the area where each pattern was not formed, but when each pattern was inspected, there were no defects such as quarrels. It was confirmed that a desired pattern was formed. Moreover, although the pattern was transferred to the transfer object using these photomask and phase shift mask, the pattern transfer was also good.

  Three quartz glass substrates having a size of 152.4 mm × 152.4 mm × 6.35 mm, which are the same as those in the above-described embodiment, are prepared by polishing the main surface and side surfaces, and these glass substrates are shown in FIG. The non-uniformity of the main surface of the glass substrate was inspected by the inspection method shown. When the size of the inspection result was confirmed by the same evaluation method as described above, it was confirmed that there was a scratch having lengths in the minor axis direction of 0.5 μm, 0.3 μm, and 0.1 μm in a certain region. A film similar to that of the above embodiment was formed on this glass substrate and patterned to obtain a phase shift mask. Although the pattern was transferred to the transfer object using these phase shift masks, the pattern transfer was also good, and the reliability of pattern formation could be improved compared to the case of the 1 μm scratch.

  Next, a comparative example for comparison with the above embodiment will be described. The glass substrate was precisely polished on the substrate main surface and side surfaces to obtain a quartz glass substrate having a size of 152.4 mm × 152.4 mm × 6.35 mm. When this glass substrate was inspected for non-uniformity on the main surface of the glass substrate by the inspection method shown in FIG. 3, it was confirmed that there was a scratch having a length in the minor axis direction of 2 μm on the main surface of the substrate in a certain region. (The length of the wound was measured with an atomic force microscope (AFM)). This scratch is considered to have been formed by a trajectory through which foreign matter has passed due to the inclusion of undesirable foreign matter or the like during the polishing process of the substrate. Using this glass substrate, a photomask and a phase shift mask were respectively produced in the same manner as in the above embodiment. When the pattern of the obtained photomask was confirmed, a crease was generated.

  Further, when the non-uniformity inside the glass substrate was inspected by the inspection method of FIG. 3, an image 30 in which bright spots as shown in FIG. 6 gathered in a spherical shape was detected in a certain region, and striae were found inside the glass substrate. It was confirmed that it existed. This striae could not be confirmed with an optical microscope. Using this glass substrate, a phase shift mask was produced in the same manner as in the above embodiment. When a pattern was transferred to a semiconductor wafer using the obtained phase shift mask, a pattern protruding from the line width was confirmed. This is because the light intensity distribution on the semiconductor wafer deviates from the design value due to the influence of striae existing inside the glass substrate and is transferred with an abnormal light intensity distribution.

  Next, another embodiment will be described. The glass substrate was precisely polished on the substrate main surface and side surfaces to obtain a quartz glass substrate having a size of 152.4 mm × 152.4 mm × 6.35 mm. The glass substrate was inspected for non-uniformity on the main surface of the glass substrate by the inspection method shown in FIG. Specifically, the type of non-uniformity (surface scratches and cracks, internal striae, foreign matter, etc.) and size (area, length, width, depth, region, etc.) pre-existing on the glass substrate in advance On the other hand, the relationship (information) of light leaking from the surface (the amount of light leaked, brightness, intensity distribution, depth from the surface) is stored in a computer, etc., and the nonuniformity tolerance is accommodated. The light information (reference setting value) and the light information detected by the inspection were compared, and the detected light information satisfied the reference setting value. Using this selected glass substrate, a photomask was produced in the same manner as in the above embodiment. When the pattern of the obtained photomask was confirmed, it was confirmed that there was no defect such as quarrel and a desired pattern was formed. Moreover, although the pattern was transferred to the transfer object using these photomask and phase shift mask, the pattern transfer was also good.

  Next, a comparative example for comparison with the above embodiment will be described. The glass substrate was precisely polished on the substrate main surface and side surfaces to obtain a quartz glass substrate having a size of 152.4 mm × 152.4 mm × 6.35 mm. Light is collected in a small area on the surface of the glass substrate, and the reflected output and transmitted output are compared and inspected. For example, the surface state inspection method described in Japanese Patent Application Laid-Open No. 58-162038 is used for inspection. Sorted out. Specifically, the transmission output and the reflection output were compared, and the output whose reflection output was below a certain reference set value was selected. Using this glass substrate, a photomask was produced in the same manner as in the above embodiment. When the pattern of the obtained photomask was confirmed, a crease was generated. When the glass substrate selected as a non-defective product was inspected by the inspection method shown in FIG. 3, light (defect) leaked from a certain area on the surface of the glass substrate was detected, and the light was set in advance. It was confirmed that the set value was exceeded. This is because the glass substrate of the comparative example includes defects that depend on the traveling direction of the inspection light, such as scratches on the substrate surface, whereas the glass substrate of the embodiment depends on the traveling direction of the inspection light. This is because it does not contain any defects that have sex.

  While the present invention has been described with reference to the embodiment, the present invention is not limited to the above embodiment. For example, the glass substrate is a glass substrate for electronic devices, but is not limited thereto, and can be applied to a glass substrate for information recording media (magnetic disk or optical disk) and a glass substrate for liquid crystal (display).

  Further, for example, the light-shielding film is not limited to chromium, and for example, a material containing chromium and at least one selected from oxygen, nitrogen, and carbon, a film of aluminum, molybdenum silicide (MoSi), or the like These may be made of a material containing at least one selected from oxygen, nitrogen, and carbon. Moreover, not only one layer but two or more layers may be formed.

  Further, the semi-transparent film (halftone film) is not limited to one made of molybdenum, silicon, and nitrogen. For example, a semi-transparent film made of molybdenum, silicon, and oxygen, molybdenum, silicon, oxygen, and nitrogen, It may be a semi-transparent film made of a metal selected from tungsten, titanium, tantalum, and chromium, silicon, and oxygen and / or nitrogen.

Further, the phase shift mask is not limited to the halftone mask described in the embodiment, but a film having a phase shift function (for example, SiO 2) between the light shielding film patterns.
Or a phase shift mask on which a film having a phase shift function of two or more layers on which an SOG film is formed is formed.

  In short, according to the present invention, the size of the recesses (surface defects such as scratches) on the main surface of the glass substrate for electronic devices can be set to the length in the major axis direction and the minor axis direction perpendicular to the major axis direction. When expressed in length, the length in the minor axis direction on the main surface when this recess is cut in a cross section perpendicular to the main surface is set to 1 μm or less, and pattern defects may occur during etching during patterning. And high-precision patterning is possible. Further, since there is substantially no non-uniform optical property with respect to transmitted light inside the glass substrate for electronic devices, appropriate exposure can be performed with a photomask or phase shift mask using this glass substrate.

  Further, in the glass substrate for electronic devices selected by a reference set value in a method for determining the presence or absence of a defect by optical change of inspection light, the defect present on the glass substrate is in the traveling direction of the inspection light. Since there is no dependency, pattern defects do not occur during patterning etching and the like, and high-precision patterning is possible, and a photomask and phase shift mask using this glass substrate are suitable. Exposure is possible.

It is typical sectional drawing which shows one Embodiment of the photomask blank and photomask which concern on this invention. It is typical sectional drawing of the phase shift mask blank and phase shift mask which concern on this invention. It is a schematic block diagram of the test | inspection apparatus which test | inspects the nonuniformity of a glass substrate. It is process drawing for demonstrating that a defect generate | occur | produces in a pattern, when a photomask is produced using the glass substrate with a crack more than a predetermined value. It is explanatory drawing for demonstrating that intensity distribution of exposure light becomes abnormal when a phase shift mask is produced using the glass substrate which has striae. It is a figure which shows the image detected when the glass substrate which has striae is test | inspected using the test | inspection apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Chrome film 2 'Chrome film pattern 3 MoSiN halftone film 3' MoSiN film pattern 4 Laser 51, 52 Mirror 53 Incident angle adjusting means 6 Driving device 7 Table 8 Lens system 9 CCD
14 wounds 22 striae

Claims (4)

A glass substrate having at least one set of main surfaces parallel to each other, at least one set of side surfaces orthogonal to the main surfaces, and a chamfered surface sandwiched between the main surfaces and the side surfaces, the main surfaces and the side surfaces Preparing a precision polished glass substrate,
Inspecting the precision-polished glass substrate by an inspection method for determining the presence or absence of a defect by optical change of inspection light, and selecting a glass substrate for an electronic device that satisfies a reference set value A manufacturing method comprising:
The inspection method in the inspection step uses laser light as inspection light, and when the optical path in the glass substrate is optically uniform, propagates in the glass substrate and totally reflects on the main surface and the side surface. And the laser beam is propagated in a repetitive manner between at least one pair of side surfaces so that the laser beam is distributed over the region to be inspected surrounded by the main surface, the side surface, and the chamfered surface. Is introduced into the glass substrate, and when there is an optically non-uniform portion in the optical path in the glass substrate, information on the light leaking from the surface is obtained and compared with a reference set value,
The light information is at least one of image information detected using a CCD , light quantity, luminance, intensity distribution, and depth from the surface,
The glass substrate for electronic devices is used when manufacturing a photomask blank by forming a thin film having a light shielding function on the main surface thereof,
The photomask blank is a phase shift mask blank;
The reference set value in the inspection step is that when a predetermined pattern is formed on a thin film of a photomask blank manufactured using the glass substrate for electronic devices, a photomask is manufactured, and the pattern is transferred using the photomask. , Select and set a value that does not cause pattern defects in the transfer pattern due to non-uniform portions inside the glass substrate for electronic devices,
When the laser beam is introduced from the chamfered surface and the optical path of the glass substrate is optically uniform, introduced so that the laser beam is emitted only from the chamfered surface,
The introduction of the laser beam is such that the incident angle to the main surface that first strikes after entering the glass substrate is larger than the critical angle, and the incident angle to the side surface is larger than the critical angle. The manufacturing method of the glass substrate for electronic devices characterized by setting as follows. A glass substrate having at least one set of main surfaces parallel to each other, at least one set of side surfaces orthogonal to the main surfaces, and a chamfered surface sandwiched between the main surfaces and the side surfaces, the main surfaces and the side surfaces Preparing a precision polished glass substrate,
Inspecting the precision-polished glass substrate by an inspection method for determining the presence or absence of a defect by optical change of inspection light, and selecting a glass substrate for an electronic device that satisfies a reference set value A manufacturing method comprising:
The inspection method in the inspection step uses laser light as inspection light, and when the optical path in the glass substrate is optically uniform, propagates in the glass substrate and totally reflects on the main surface and the side surface. And the laser beam is propagated in a repetitive manner between at least one pair of side surfaces so that the laser beam is distributed over the region to be inspected surrounded by the main surface, the side surface, and the chamfered surface. Is introduced into the glass substrate, and when there is an optically uneven portion in the optical path in the glass substrate, information on light leaking from the surface is obtained and compared with a reference set value,
The light information is at least one of image information detected using a CCD , light quantity, luminance, intensity distribution, and depth from the surface,
The glass substrate for electronic devices is used when producing a photomask blank by forming a thin film having a light shielding function on the main surface thereof,
The reference set value in the inspection process is selected such that when a predetermined pattern is formed by wet etching on a thin film of a photomask blank manufactured using the glass substrate for electronic devices, a pattern defect does not occur in the pattern. Set
When the laser beam is introduced from the chamfered surface and the optical path of the glass substrate is optically uniform, introduced so that the laser beam is emitted only from the chamfered surface,
The introduction of the laser beam is such that the incident angle to the main surface that first strikes after entering the glass substrate is larger than the critical angle, and the incident angle to the side surface is larger than the critical angle. The manufacturing method of the glass substrate for electronic devices characterized by setting as follows. A thin film having at least a light shielding function is formed on a main surface of the glass substrate for an electronic device obtained by the method for manufacturing the glass substrate for an electronic device according to any one of claims 1 and 2. A method for manufacturing a photomask blank. To claim 1 or main surface of the glass substrate for an electronic device obtained by the production method of the glass substrate for an electronic device according to any one of 2, forming a thin film pattern having at least the light-shielding function that is patterned A method of manufacturing a photomask characterized by the above.

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