JP2012047732A - Transmittance measuring instrument, photomask transmittance inspection device, transmittance inspection method, photomask manufacturing method, pattern transfer method, and photomask product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmittance measuring instrument capable of accurately measuring the film transmittance of a fine pattern (e.g., a fine light-semitransmitting film pattern formed on a transparent substrate).SOLUTION: In measuring the film transmittance of a fine pattern and the like of a light-semitransmitting film formed on a transparent substrate, light of a measurement wavelength is converged on the light-semitransmitting film to be a measurement object so as to be the smallest diameter (beam waist) and transmitted, and the whole transmitted light is subsequently collected in an integrating sphere and is detected by a detector.

Description

  The present invention relates to a transmittance measuring apparatus, for example, a transmittance measuring apparatus that measures the light transmittance of a fine portion such as a photomask having a transfer pattern formed by processing an optical film formed on a transparent substrate.

  Conventionally, a photolithography process is used in manufacturing an electronic device such as a liquid crystal device. That is, a resist film formed on a layer to be etched (hereinafter also referred to as a transfer target) is exposed under predetermined exposure conditions using a photomask having a predetermined transfer pattern, The transfer pattern is transferred, and the resist film is developed to form a resist pattern. And the process of etching a to-be-transferred body is performed using this resist pattern as a mask.

  In recent years, there has been a demand for cost reduction in the manufacture of electronic devices such as liquid crystal display devices, and a reduction in the number of masks in the manufacturing process is required. Specifically, a method of reducing the number of masks to be used by using a multi-tone photomask (hereinafter also referred to as a photomask) having a light-shielding portion, a light-transmitting portion, and a semi-light-transmitting portion has been proposed. That is, by having a semi-transparent part in addition to the light-shielding part and the translucent part, the resist film formed on the transferred body is exposed and developed using a photomask having three gradations, thereby producing a partial Thus, it is possible to form resist patterns having different amounts of residual film and different amounts of residual film depending on the portions. In this case, since the process that conventionally used two masks can be performed with one mask, the number of masks used can be reduced and the production efficiency is increased. Further, in order to fabricate a multi-tone photomask having four or more gradations, a mask having a semi-transparent portion formed of two or more types of semi-transparent films having different light transmittances has been proposed (for example, Patent Document 1). If such a photomask having four gradations is used, a process that has conventionally used three masks can be performed with one mask. Here, the semi-transparent portion means that when a pattern is transferred to a transfer object using a mask, the amount of exposure light transmitted therethrough is reduced by a predetermined amount, and the photoresist film on the transfer object after development is developed. A portion that controls the amount of remaining film is referred to, and a photomask including such a semi-transparent portion together with a light-shielding portion and a translucent portion is called a multi-tone photomask.

JP 2009-258250 A

  As a photomask for manufacturing a liquid crystal display device, for example, a portion corresponding to a source and a drain in a TFT (thin film transistor) is formed as a light shielding portion, and a portion corresponding to a channel portion located adjacent to the source and drain Can be used as a semi-transparent portion. In recent years, with the miniaturization of the pattern of the TFT channel portion and the like, a finer pattern is required also in the multi-tone photomask, and the portion corresponding to the channel width in the pattern of the TFT channel portion, that is, the light shielding film The width of the semi-translucent portion in between also tends to be miniaturized. This is effective for improving the brightness of the liquid crystal and the reaction speed, but it is not easy to manufacture a photomask having such a fine semi-translucent portion. For example, a transfer pattern in which the line width of the semi-translucent portion is 7 μm or less, and further 5 μm or less must be able to be transferred precisely. This trend toward miniaturization is further advanced, and it can be assumed that a line width of 3 μm or less is required.

  The role of the semi-transparent portion in the multi-tone photomask is to control the amount of light transmitted through the mask to give a desired exposure amount to the transfer target. It is necessary to accurately measure and evaluate the light transmittance of the semi-translucent portion. That is, it is necessary to grasp the film transmittance of the film formed in the semi-translucent portion (regardless of the film structure of single layer or stacked layer, the resulting light transmittance of the film is referred to as the film transmittance). In general, as a method for measuring the film transmittance of a semi-transparent portion formed on a transparent substrate, (1) a method of actually measuring using a spectrophotometer, (2) a microscope using visible light as a light source, 2 Obtain a two-dimensional image, and based on the image density at the desired point in the image, the transmittance at the desired wavelength from the conversion formula (preliminarily determined) according to the image density and the film characteristics (wavelength dependence of the transmittance) It is considered that a method for predicting can be used.

  The method (1) can be said to have high reliability in terms of actual measurement, but is not suitable for measurement of a minute portion because the spot diameter on the measurement object is large due to the limitations of the apparatus. For example, the limit line width at which the transmittance can be measured with a spectrophotometer is about 1 to 5 mm depending on the specifications of the apparatus. Therefore, when the line width of the portion to be measured is less than 5 mm, the reliability of the measurement value is lowered due to the influence of the surrounding transmittance. When the line width of the portion to be measured is less than 1 mm, it becomes almost impossible to measure. For this reason, there is a problem that a reliable transmittance cannot be measured for a measurement region having a line width of the order of μm (for example, a fine semi-translucent portion).

  Although the above method (2) can measure the transmittance of a small measurement region, it needs to be converted to a desired wavelength after measurement with visible light, and the spectral characteristics of the film formed on the semi-translucent portion are preliminarily determined. There is a problem that it is difficult to measure a reliable and accurate transmittance such that the grasping is complicated and an error occurs depending on the film characteristics.

  The present invention has been made in view of such points, and accurately measures the film transmittance of a fine pattern (for example, a semi-transparent portion obtained by patterning a semi-transparent film formed on a transparent substrate). Another object is to provide a possible transmittance measuring device.

  The transmittance measuring apparatus according to the present invention includes a light source device that emits a test light beam, a condensing optical system that collects the test light beam and guides the test light beam to a subject, receives the transmitted light beam that has passed through the subject, A light detection device for detecting, and a calculation device for determining the light transmittance of the subject based on the amount of light detected by the light detection device, wherein the collected test light beam is in the vicinity of a beam waist. The relative positions of the light source device, the condensing optical system, and the subject are adjusted so that the light enters the subject to be examined.

  In the transmittance measuring apparatus of the present invention, the light source device includes a laser light source, and when the effective diameter of the condensing lens provided in the condensing optical system is 1, the light is incident on the condensing lens as parallel light. The diameter of the test light beam is preferably 0.4 or more and 0.6 or less.

  In the transmittance measuring device according to the present invention, it is preferable that the photodetecting device has an integrating sphere provided with a photodetector inside.

  In the transmittance measuring apparatus according to the present invention, the integrating sphere has an incident port through which the transmitted light beam is incident, and a port diameter of the incident port of the transmitted light beam at a position where the transmitted light beam is incident. The integrating sphere is preferably arranged so as to be larger than the diameter.

  In the transmittance measuring apparatus of the present invention, it is preferable that the condensing optical system includes a first collimator lens and a condensing lens.

  In the transmittance measuring apparatus of the present invention, the light source device and the light collecting device are arranged to adjust the relative positions of the light source device, the condensing optical system, and the subject in a plane parallel to the main plane of the subject. It is preferable to provide a moving device for moving the optical optical system or moving the subject.

  In the transmittance measuring apparatus of the present invention, it is preferable that a second collimator lens for adjusting a diameter of the transmitted light beam is provided between the subject and the light detection device.

  In the transmittance measuring apparatus according to the present invention, the condensing optical system includes a light distribution adjusting unit that makes the light intensity distribution in a plane perpendicular to the optical axis of the test light beam larger in the central portion than in the peripheral portion. Is preferred.

  According to the photomask transmittance inspection apparatus of the present invention, the transmittance of a photomask having a transfer pattern formed by patterning an optical film formed on a transparent substrate is measured at a specific inspection position of the transfer pattern. A transmittance inspection device for measuring, a light source device for emitting a test light beam, a condensing optical system for condensing the test light beam and guiding it to a photomask, and receiving a transmitted light beam transmitted through the photomask, And a calculation device that obtains the light transmittance at the inspection position of the photomask based on the amount of light detected by the light detection device, and the collected test light beam is The relative positions of the light source device, the condensing optical system, and the photomask are adjusted so that they are incident on the inspection position of the photomask near the beam waist. And said that you are.

  In the photomask transmittance inspection apparatus according to the present invention, when the light source device includes a laser light source and the effective diameter of the condensing lens provided in the condensing optical system is 1, the condensing lens is converted into parallel light. It is preferable that the diameter of the test light beam incident on is 0.4 or more and 0.6 or less.

  The transmittance inspection method of the present invention is a transmission for measuring the transmittance of a photomask having a transfer pattern formed by patterning an optical film formed on a transparent substrate at a specific inspection position of the transfer pattern. The test light beam emitted from the light source device is collected at the inspection position of the photomask, transmitted through the photomask in the vicinity of the beam waist of the test light beam, and the transmitted light beam diffused after the transmission, The light is incident on the light detection device, and the light transmittance T at the inspection position is obtained based on the light amount L detected by the light detection device.

  In the transmittance inspection method of the present invention, the light detection device has an integrating sphere provided with a photodetector inside, and the transmitted light beam is in a state where the intensity is uniformed by repeated diffuse reflection within the integrating sphere. Therefore, it is preferable that the light amount is detected by the photodetector.

  In the transmittance inspection method of the present invention, it is preferable that the transfer pattern has a translucent part that transmits exposure light and a semi-transparent part that blocks part of the exposure light.

  In the transmittance inspection method of the present invention, it is preferable that the transfer pattern further includes a light shielding portion that substantially shields exposure light.

  In the transmittance inspection method of the present invention, the photomask is a multi-tone photomask for forming a resist pattern having a plurality of different resist residual film values on a resist film formed on a transfer target. It is preferable.

  In the transmittance inspection method of the present invention, a test light beam emitted from the light source with any part on a transparent substrate on which an optical film is not formed or a part on which the optical film of the photomask is not formed as a reference position In the vicinity of the beam waist of the test light beam, pass through the reference position of the transparent substrate or the photomask, and transmit the transmitted light beam diffused after transmission to the light detection device, It is preferable to obtain the light transmittance T at the inspection position of the photomask using the light quantity L0 detected by the detection device and the light quantity L.

  The photomask manufacturing method of the present invention prepares a photomask blank having an optical film formed on a transparent substrate, forms a transfer pattern by patterning the optical film, and inspects the transfer pattern. In the photomask manufacturing method, the transmittance inspection method described above is used in the inspection.

  The pattern transfer method of the present invention is characterized in that a transfer pattern of the photomask is transferred onto a transfer object using a photomask manufactured by the above-described photomask manufacturing method and an exposure apparatus.

  The photomask product of the present invention has the light transmittance T at the desired inspection position of the photomask obtained by the transmittance inspection method in a state associated with the photomask.

  According to the present invention, the light transmittance with respect to the measurement wavelength can be precisely determined even for a narrow region such as a fine pattern.

It is a figure which shows an example of the transmittance | permeability measuring apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the transmittance | permeability measuring apparatus which concerns on embodiment of this invention. It is a figure explaining the spot light on a subject in case parallel light of uniform intensity distribution is incident on a condensing lens. It is a figure explaining the case where the light of a Gaussian distribution is entered into a condensing lens. It is a figure explaining the case where the light of a Gaussian distribution is entered into a condensing lens. It is a figure which shows the transmittance | permeability measuring apparatus which directly enters into the photodetector the transmitted light which permeate | transmitted the measuring object. It is a figure which shows an example of a light distribution adjustment means. It is a figure which shows an example of the transmittance | permeability measuring apparatus of this invention, or the transmittance inspection apparatus of a photomask. It is a figure which shows an example of the transmittance | permeability measuring apparatus of this invention, or the transmittance inspection apparatus of a photomask. It is a figure which shows an example of the multi-tone photomask applied to the transmittance measuring apparatus of the present invention. It is a figure which shows an example of the transfer process by the multi-tone photomask shown in FIG. It is a figure which shows an example of the manufacturing method of a multi-tone photomask.

  The inventor has a light source device that emits a test light beam, a condensing optical system that condenses the test light beam and guides it to a subject, and a light detection that detects a light amount by receiving a transmitted light beam that has passed through the subject. A transmittance measuring device comprising: a device; and a computing device for obtaining the light transmittance of the subject based on the amount of light detected by the light detecting device, wherein the collected test light beam is in the vicinity of a beam waist In this case, the relative position of the optical system and the subject is adjusted so as to be incident on the examination position of the subject. The knowledge that the transmittance itself can be measured accurately was obtained. Below, the structural example of the transmittance | permeability measuring apparatus of this invention is demonstrated with reference to drawings.

  The transmittance measuring apparatus shown in FIG. 1 includes at least a light source 101 and a condensing optical system that guides a light beam emitted from the light source 101 to a subject (here, a collimator lens 102 that converts the emitted light from the light source 101 into a parallel light beam 111) And a collimating lens 103 for condensing the collimated light beam 111 from the collimator lens 102 onto the subject 120), the transmitted light beam 112 diffuses after the test light beam passes through the subject 120. A light detection device for detecting light is provided. The photodetector includes an integrating sphere 105 that guides the transmitted light beam 112 from the incident port 104 and spatially integrates it by diffuse reflection, and then guides it to the photodetector 106. The transmitted light beam 112 transmitted through the subject 120 is diffused behind the subject 120, but the integrating sphere 105 is arranged so that the diameter of the incident port 104 is larger than the diameter of the transmitted light beam 112 at the position of the incident port 104. In this way, the transmitted light beam 112 can be all taken into the integrating sphere 105. Hereinafter, the components of the transmittance measuring device will be specifically described.

<Light source device>
The light source device includes at least a light source 101. The light source 101 only needs to emit predetermined light to the subject 120. In the case where the subject 120 is a photomask having a transfer pattern including a semi-translucent portion, light having a wavelength included in a light source of an exposure machine used when the photomask is used can be used. For example, a mercury lamp, a halogen lamp, a xenon lamp, an LED light source, or the like that can emit light in a wavelength range including i-line, g-line, and h-line, or a representative wavelength therein can be used. Further, a laser that emits light of a specific single wavelength may be used as the light source 101.

  The laser light can have a substantially Gaussian distribution of light intensity in the beam (light beam). In other words, on the plane perpendicular to the optical axis, the light intensity at the center of the beam (near the optical axis) is relatively large and decreases as it moves away from the optical axis (goes to the periphery). On the other hand, the above-mentioned lamp and LED including a plurality of wavelengths do not have an intensity distribution like the laser light, and the light intensity in the light beam is almost uniform. In this case, in order to have a light intensity distribution similar to laser light, a filter for the purpose of adjusting the light distribution of the light beam may be provided. This point will be described later.

  In the case where a mercury lamp, a halogen lamp, a xenon lamp, or the like is used as the light source 101 used in the light source device, light having a plurality of wavelengths is emitted from the light source 101. Therefore, light having a desired wavelength is selectively selected. A transmissive wavelength selective filter 121 can be provided. On the other hand, when the light source 101 emits light of a specific wavelength, such as a laser or LED, the wavelength selection filter 121 may not be provided. Alternatively, it is also useful to apply a light source device equipped with a plurality of single wavelength LEDs or laser light sources. In this way, by switching and using a plurality of light sources having different single wavelengths, it is possible to measure the transmittance for each different wavelength. In addition, light of a single wavelength emitted from these LEDs and laser light sources is suitable because it can be easily condensed by the optical system and the diameter of the light beam can be reduced.

  When using these highly directional light sources, the diameter of the emitted light beam (beam diameter) is enlarged to a predetermined magnification using an optical element such as a beam expander (not shown). It is preferable to introduce into the collimator lens 102. Further, when a laser light source is used as the light source 101, it is preferable that the oscillation is in a single mode, and the shape of the beam diameter is preferably a circle or an ellipse.

<Condensing optical system>
In this aspect, the condensing optical system includes a collimator lens 102 and a condensing lens 103. The collimator lens 102 has a function of guiding the light emitted from the light source 101 to the condenser lens 103 as a parallel light beam 111. Thereby, the light emitted from the light source 101 can be efficiently guided to the condenser lens 103.

  The collimator lens 102 is desirably adjusted so that the light emitted from the light source 101 (test light beam) becomes parallel light. However, the collimator lens 102 (hereinafter also referred to as the first collimator lens) does not necessarily require the light emitted from the light source 101 (test light beam) to be completely parallel light. The collimator lens 102 adjusts the light (test light beam) emitted from the light source 101 to an appropriate light beam diameter so that it can be incident on the diameter (effective diameter) of a condensing optical system (condensing lens 103) described later. It is desirable to make it.

  The condensing lens 103 has a function of condensing light so that the test light beam is condensed at the inspection position of the subject 120. That is, the test light beam is arranged so as to be incident on the inspection position of the subject 120 in the vicinity of the portion (beam waist) where the diameter of the test light beam is the smallest. For example, when the subject 120 is a photomask and the inspection position is a semi-transparent portion in the transfer pattern, the semi-transparent portion is focused. In this way, since the position to be inspected can be measured at the portion where the diameter of the test light beam is the smallest, it is advantageous for measuring a fine pattern. Note that in the conventional method of actually measuring the transmittance of a minute region using a spectrophotometer, the light transmittance of a peripheral portion (for example, a light-shielding portion or a light-transmitting portion) around a desired measurement position is measured in a measurement spot. However, the transmittance measuring device shown in the present embodiment guides the test light beam only to the region to be inspected (for example, the semi-translucent portion) and transmits it. Therefore, it is possible to accurately measure the film transmittance of the semi-transparent film itself.

Here, the vicinity of the beam waist refers to a region having a diameter not exceeding 1.1 times the diameter when the portion having the smallest diameter of the light beam collected by the condenser lens 103 is defined as the beam waist. . Further, the diameter of the light beam means that the light intensity is 13.2 when the light intensity at the center (that is, the maximum light intensity) is 100% on the cut surface when the light beam is cut in a plane perpendicular to the optical axis. The diameter of a circle in an area of 5% or more (1 / e ² of the maximum light intensity at the center) or the major axis of an ellipse can be used.

  In order to satisfy the above relationship, it is important to adjust the relative positions of the condensing lens 103 and the subject 120 in the optical axis direction, but the condensing lens 103 is moved while the subject 120 is fixed as described above. Conversely, the subject 120 may be moved relative to the condenser lens 103. Or you may move both.

  The numerical aperture (NA) of the condensing lens 103 is set to 0.25 to 0.65 (NA = 0.25 to 0.65) from the viewpoint of the shape of the condensing spot and the incident angle dependency on the subject 120. It is preferable. If the NA is too small, the focused spot shape cannot be made sufficiently small at the inspection position. On the other hand, if the incident angle on the subject 120 becomes too large, the ratio of light rays that are incident on the subject 120 obliquely (in a direction other than perpendicular to the subject surface) increases, and the reliability of transmittance measurement is increased. Therefore, it is preferable to set the upper limit of NA to 0.65.

  In consideration of the above, the numerical aperture of the condensing lens 103 can be appropriately set according to the area of the region to be measured (the area of the semi-transparent portion of the photomask), the measurement wavelength, and the like.

<Photodetection device>
The light detection apparatus includes an integrating sphere 105 and a photodetector 106. The integrating sphere 105 plays a role of making the light (transmitted light beam 112) incident from the incident port 104 spatially integrate by diffuse reflection on the inner wall surface of the sphere and make it uniform and enter the photodetector 106. In FIG. 1, the test light beam emitted from the light source device is condensed on the surface of the subject 120 and transmitted, and then the transmitted light beam 112 enters the integrating sphere 105 via the incident port 104, and the inside of the integrating sphere 105 Is spatially integrated by the diffuse reflection. Further, the integrating sphere 105 is arranged so that all of the transmitted light beam 112 diffusing behind the subject 120 is taken into the integrating sphere 105 from the incident port 104.

  The photodetector 106 (also referred to as a power meter) can be installed by an opening provided in the integrating sphere 105, which is different from the incident port 104. The photodetector 106 is configured to receive light that has been spatially integrated by the integrating sphere 105 and made uniform (averaged). That is, all the light that has passed through the inspection position of the subject 120 (the range in which the test light beam from the light source device is collected) is averaged, and light proportional to the intensity is uniformly incident on the photodetector 106. The light transmission amount at the inspection position of the subject 120 can be measured with high accuracy, and the light transmittance can be obtained based on the light transmission amount. The photodetector 106 is preferably provided inside the integrating sphere 105. Here, the inside is a position where the light integrated by the integrating sphere 105 can be incident on the photodetector 106, and can include, for example, the inside and the inside of the integrating sphere 105. However, when the photodetector 106 cannot be installed inside the integrating sphere 105 due to mechanical restrictions, etc., there is a demerit such as a decrease in the amount of light incident on the photodetector 106, but the light integrated by the integrating sphere 105 is reduced. The installation position of the photodetector 106 can be changed within a range of positions where the light can enter the photodetector 106. For example, the photodetector 106 can be installed outside the integrating sphere 105. In addition, in order to integrate spatially within the integrating sphere 105 and make it sufficiently uniform (averaged), the diameter of the incident port 104 is preferably ¼ or less of the diameter of the integrating sphere 105.

  Further, it is preferable that the integrating sphere 105 has an inner wall covered with a material having a reflectance of 0.8 or more with respect to the test light beam.

  As shown in FIG. 6, without using the integrating sphere 105, the transmitted light beam 112 that has passed through the subject 120 is directly incident on the light receiving portion of the photodetector 123, and the transmitted light beam 112 can be directly detected by the photodetector 123. Is possible. In this case, in general, the photodetector 123 has a flat light receiving portion and has an incident angle dependency with respect to the light receiving portion, so that it is necessary to install the light receiving portion perpendicular to the optical axis. When the transmitted light beam 112 that has passed through the subject 120 is directly incident on the photodetector 123, all of the transmitted light beam 112 is perpendicular even if the light receiving unit is installed perpendicular to the optical axis of the diffused transmitted light beam 112. Since it is not possible to enter the light, a measurement error may occur. In addition, since the light receiving surface of the photodetector 123 must be larger than the diameter of the transmitted light beam 112 and the size thereof is limited, when the entire transmitted light beam 112 is incident on the photodetector 123, The distance between the photodetectors 123 must be very short. On the other hand, as shown in FIG. 1, when the integrating sphere 105 is used, the transmitted light beam 112 is incident from the incident port 104 having a larger diameter than the light receiving surface of the photodetector 106 and is spatially integrated by the integrating sphere 105. Since the uniformized (averaged) light is incident on the photodetector 106, even if the diameter of the transmitted light beam 112 is larger than the light receiving surface of the photodetector 106, the integrating sphere 105 having the corresponding size is selected, so that the above-described device is obtained. The above limitation is eliminated, and measurement with excellent accuracy is possible.

  Further, in the case of measuring the film transmittance with higher accuracy, the incident light (transmitted light beam 112) to the integrating sphere 105 can be fixed at a certain angle (solid angle). In this case, as shown in FIG. 2, a collimator lens 122 (hereinafter also referred to as a second collimator lens) that uses the transmitted light beam 112 as parallel light can be provided between the subject 120 and the integrating sphere 105. As a result, it becomes easy for all of the transmitted light beam 112 to enter the incident port 104 of the integrating sphere 105, and the incident angle is within a certain range, so that the measurement accuracy of the photodetector 106 can be further improved. Become.

  Further, since the diameter of the transmitted light beam 112 can be reduced by providing the second collimator lens 122 between the subject 120 and the integrating sphere 105, the integrating sphere can be obtained without making the diameter of the incident port 104 very large. 105 can be arranged at a desired distance from the subject 120. That is, it is possible to freely set the arrangement of the integrating spheres 105, and there is an effect that the degree of freedom of installation of the optical element is improved.

  It should be noted that the second collimator lens 122 here is not necessarily required to make the transmitted light beam 112 completely parallel light, like the first collimator lens 102 described above. It is only necessary that the transmitted light beam 112 can be reliably taken into the integrating sphere 105 by reducing the light beam diameter. In other words, the second collimator lens 122 can function as a light beam diameter adjusting means for arranging the integrating sphere 105 at a desired position.

  In the apparatus of FIG. 6 as well, the transmitted light beam that has passed through the subject 120 can be collimated by the collimator lens and incident on the photodetector 123. However, since the photodetector 123 may detect stray light other than the transmitted light beam 112 (light that comes from a light source inside or outside the apparatus and enters unintentionally from a place other than the inspection position), integration is possible. The apparatus of FIG. 1 or 2 using a sphere is more preferable.

<Transmittance measuring device>
FIGS. 8 and 9 illustrate the transmittance measuring device on which the light source device, the condensing optical system, and the light detection device described above are mounted.

  In this aspect, the light source device and the condensing optical system can be arranged at a desired position on the subject (photomask) 120 in a state where the optical axes thereof are aligned. Further, the optical detection device also has its axis substantially coincided with the optical axis so that the transmitted light beam transmitted through the subject 120 can be completely incident. In this way, it is possible to detect the light transmittance at a desired inspection position of the subject 120.

  Here, the light source device and the condensing optical system are integrally held with the optical axes aligned (unit A), and can be moved while the movement direction is controlled by the unit A driving rail. Then, it can be arranged at a desired position in a plane parallel to the main plane of the subject 120. On the other hand, the photodetection device (unit B) can be moved in a plane parallel to the main plane of the subject 120 while the movement direction is controlled by the unit B driving rail. Unit A and unit B face the main plane of the subject from both sides, and the optical axes of both coincide with each other when measuring light transmittance. When the collimator lens 122 is provided on the light detection device side (see FIG. 2), it can also be installed as a part of the unit B with the optical axes aligned.

  The unit A and the unit B are a unit A moving device 301 and a unit B moving device for moving each to a desired position in a plane parallel to the main plane of the subject 120 (that is, in a plane perpendicular to the optical axis). These mobile devices are respectively connected to 302 and controlled by the control device 300 (see FIG. 9).

  Furthermore, the subject 120 and the units A and B can be adjusted in relative position in the optical axis direction by a position adjusting mechanism (not shown). That is, the mutual position of the test light beam emitted from the light source device is so precise that the light beam is guided to the subject 120 by the condensing optical system, and the light beam is incident on the inspection position of the subject 120 near the beam waist. Adjusted. This position adjusting mechanism can be included in the unit A moving device 301 and the unit B moving device 302. In the unit A, the mutual position of the light source device and the condensing optical system in the optical axis direction, and the mutual position of the structural components (the light source 101, the first collimator lens 102, etc.) in the light source device are also set as necessary. Needless to say, it is adjustable.

  The amount of light detected by the light detection device is sent to the calculation device 303, and the light transmittance of the subject can be calculated. The arithmetic unit 303 can also store and save parameters necessary for the calculation of the light transmittance in advance using an accompanying memory.

  The apparatus of the present invention further includes a subject holder that holds the subject 120. The subject holder of this aspect can hold a photomask having a square shape with a side of 300 mm or more. For example, it is preferable that a rectangular photomask having a side of 300 to 1800 mm can be held.

  In the above-described embodiment, the subject 120 is fixed and both units (A, B) are movable. However, the opposite may be possible, and both may be movable. In addition, as shown in FIG. 8, the subject holder may hold the subject 120 substantially horizontally, or may hold the subject 120 substantially vertically.

<Transmittance measurement method>
An object (here, a photomask) 120 is set on the transmittance measuring device, and the light transmittance at a desired position of a transfer pattern formed on the photomask 120 can be measured. For example, when the photomask 120 is provided with a semi-transparent portion that transmits part of the exposure light, even when the semi-transparent portion has a fine size, An accurate light transmittance of the semi-translucent portion can be measured without being affected by the patterns (translucent portion, light-shielding portion, etc.) arranged around the periphery.

  For example, the photomask 120 that is the subject is set in the subject holder of the apparatus of the present invention. Next, the unit A and the unit B are moved in a plane parallel to the main plane of the photomask 120 in a state where the optical axes of the units A and B coincide with each other, and set at the position of the semi-transparent portion where the transmittance is to be obtained. To do. Here, when the photomask 120 that is the subject is a large mask for a liquid crystal display device, the exposure light wavelength is i-line to g-line, so a light source having a wavelength region substantially equal to that is used. It is useful to measure. Alternatively, it is also useful to perform measurement using a representative wavelength (for example, i-line) used as a reference for transmittance measurement by the mask user.

  The position of the unit A and unit B in the plane parallel to the mask surface is defined, and the test light beam emitted from the light source device passes through the condensing optical system, and the vicinity of the beam waist is the photomask to be measured. The relative position between the unit A and the subject is adjusted so as to be positioned at the semi-transparent portion 120. Next, the light detection device is positioned so that the transmitted light beam 112 after the test light beam passes through the semi-translucent portion is reliably incident from the incident port 104 of the integrating sphere 105 of the light detection device. At this time, the output (transmitted light amount L) of the photodetector 106 placed in the integrating sphere 105 is taken into the arithmetic unit 303.

When obtaining the film transmittance T in the semi-transparent portion of the photomask 120, the reference transmission amount L0 of the transparent substrate before the film is formed can be obtained in advance. This is referred to in the same manner as described above for a part of the transparent substrate on which no film is formed, or on a part of the transfer pattern of the photomask 120 where no film is formed (also referred to as “reference position”). It is obtained by obtaining the transmitted light amount L0. Then, if the light transmission amount L of the semi-translucent part is obtained as described above, the light transmittance T of the semi-translucent part is:
T = L / L0
Can be obtained as

<Subject>
The subject 120 of the transmittance measuring apparatus shown in this embodiment may be any object that transmits light. As a suitable example in which transmittance can be measured using the transmittance measuring apparatus shown in this embodiment, a photomask having a transfer pattern obtained by patterning an optical film formed on a transparent substrate is used. A mask is mentioned.

  The optical film can be a film that shields (that is, partially transmits) at least a part of the exposure light (referred to as a semi-transparent film). This is used when a resist film formed on a transfer object is exposed using a photomask to reduce the film by a desired amount to form a resist pattern having a desired shape.

  In particular, in a multi-tone photomask, a resist pattern having a plurality of different residual film amounts can be formed, and a desired electronic device can be manufactured using the resist pattern, which is extremely useful. For example, the photomask applied to the present invention can be a multi-tone photomask used for manufacturing a liquid crystal display device. In addition to a light transmitting portion and a light shielding portion, one or more types of exposure light transmittance And a semi-translucent portion.

  FIG. 10 illustrates a multi-tone photomask for the above application. A three-tone photomask 20 having a desired transfer pattern (semi-transparent film pattern 201p, light-shielding film pattern 202p) by patterning the semi-transparent film 201 and the light-shielding film 202 formed on the transparent substrate 200; It has become. Here, the semi-translucent portion 215 has a fine width and is adjacent to the translucent portion 220 and the light shielding portion 210. For this reason, it is difficult in the prior art to accurately grasp the light transmittance of the semi-transparent film formed in the semi-transparent portion after patterning.

  It is possible to measure the light transmittance before the formation of the light-shielding film and at the stage where only the semi-translucent film is formed (the photomask blank forming process described later), but after patterning is performed through a plurality of processes. It is unclear whether or not this shows the same transmittance when it is a finished photomask. Therefore, it is necessary to measure the transmittance of a fine semi-transparent portion as a photomask.

  FIG. 11 shows a transfer process using the above multi-tone photomask. That is, when it is desired to form a three-dimensional pattern on the transferred object 50 in which a plurality of thin films 501 formed on the transparent substrate 500 are laminated, the pattern is transferred using an appropriate photomask. Here, a resist pattern 502p having a plurality of different residual film amounts is formed on the positive resist layer 502 formed on the transfer object, using the multi-tone photomask 20. In this way, pattern processing for two photomasks can be performed with one photomask.

  The transmissivity of the translucent film according to the present invention is measured when the transfer pattern in the above multi-tone photomask is fine (for example, the width is 1 mm or less. The exposure light transmittance of the semi-translucent portion can be measured because the necessity of application is high and the effect of the present invention is particularly remarkable when the thickness is 2 to 100 μm.

  For example, when using an existing spectrophotometer with a large measurement spot when trying to measure the film transmittance of the semi-transparent part adjacent to the light-shielding part, the semi-transparent light at the position to be inspected is in the measurement field of view. It is impossible to arrange only the portion, and an accurate light transmittance cannot be obtained. According to the present invention, since the measurement visual field can be the diameter of the beam waist formed by the condensing optical system, a minute spot can be measured.

  As described above, an optical film (here, a semi-transparent film that transmits part of exposure light) formed on a transparent substrate has been manufactured by increasing the number of gradations and pattern miniaturization of a photomask in recent years. It is required to accurately measure the membrane transmittance of a later photomask, and it is very effective to use the transmittance measuring device described in this embodiment for such an object. Become.

  That is, in the manufactured photomask, there is a semi-translucent portion having an area smaller than the area that can be measured by a conventional measuring method using a spectrophotometer, and the film transmittance of this portion can be accurately known. It is extremely important for photomask inspection and product warranty.

  For example, such a photomask is a photomask for manufacturing a liquid crystal display device, and a large-sized mask having a side of 300 mm or more can be used.

  In addition, a multi-tone photomask (three gradations) having a light-transmitting portion, a semi-light-transmitting portion, and a light-shielding portion is used for manufacturing a thin film transistor (TFT) or a color filter (CF) used in a liquid crystal display device. It is done. Alternatively, a multi-tone photomask having four or more gradations having two or more types of semi-transparent portions having different transmittances can be given.

  Furthermore, even a two-tone photomask can be usefully applied as the subject of the present invention when an optical film having a predetermined transmittance is used for the light shielding portion.

  As an object to be applied to the present invention, a multi-tone photomask, an inspection method thereof, and a manufacturing method thereof, which can obtain the remarkable effects of the present invention, will be described.

  The multi-tone photomask can be manufactured, for example, by the method shown in FIG. That is, first, a photomask blank 20b in which a semi-transparent film 201 and a light-shielding film 202 are laminated in this order on a transparent substrate (200) and a resist 203 (here, a positive resist) is applied is prepared (see FIG. 12A). ).

The transparent substrate 200 is made of, for example, quartz (SiO ₂ ) glass, SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , RO (R is an alkaline earth metal), R ₂ O (R ₂ is an alkali metal) or the like. It is comprised as a flat plate which consists of glass etc. which contain. The main surface (front surface and back surface) of the transparent substrate 200 is polished to be flat and smooth. The transparent substrate 200 can be a square having a side of about 500 mm to 1800 mm, for example. The thickness of the transparent substrate 200 can be set to about 3 mm to 20 mm, for example.

The translucent film 201 is made of a material containing, for example, chromium (Cr), and is made of a chromium compound such as chromium nitride (CrN), chromium oxide (CrO), chromium oxynitride (CrON), or chromium fluoride (CrF). be able to. These semi-transparent films 201 are etched using a chromium etching solution made of pure water containing, for example, ceric ammonium nitrate ((NH ₄ ) ₂ Ce (NO ₃ ) ₆ ) and perchloric acid (HClO ₄ ). It is configured as possible. Alternatively, a metal silicide compound made of a material containing a metal material such as molybdenum (Mo) and silicon (Si) can be used. For example, it is made of MoSi, MoSix, MoSiN, MoSiON, MoSiCON or the like. This type of translucent film 201 is configured to be etched using a fluorine (F) -based etching solution (or etching gas).

  The light shielding film 202 can be made of chromium (Cr) or a chromium compound containing chromium as a main component. In addition, by laminating a Cr compound (CrO, CrC, CrN, etc.) having a predetermined composition on the surface of the light shielding film 202 (not shown), the surface of the light shielding film 202 can have a light reflection suppressing function. The light shielding film 202 is configured to be etched using the above-described chromium etching solution.

  The light shielding film 202 substantially shields the exposure light (i-line to g-line), and the light transmitting part 220 is configured to transmit the exposure light substantially 100%. The semi-transparent film 201 can have a film transmittance of 3% or more and 80% or less when the transmittance of the transparent substrate is 100%. As a semi-transparent film used for a semi-transparent portion of a multi-gradation photomask having three or more gradations as a photomask for manufacturing TFTs, it is easy to process a transfer object by a mask user by 5 to 60%. In terms, 20 to 60% is preferable. In addition, you may evaluate what has the said transmittance | permeability using a representative wavelength (for example, i line | wire).

  Furthermore, in a photomask having two gradations (a light shielding part and a light transmitting part), when the light shielding film used for the light shielding part has a certain transmittance, the transmittance is preferably 3 to 20%, and more preferably 5%. -15%.

  A predetermined pattern is drawn on the photomask blank and developed to obtain a first resist pattern (203p) (see FIG. 12B). The light shielding film 202p is formed by etching the light shielding film 202 using this as a mask (see FIG. 12C).

  After peeling off the resist pattern 203p, a resist 204 is applied again on the entire surface (see FIG. 12D). Then, the second resist pattern (204p) is obtained by the second drawing and development (see FIG. 12E). The semi-transmissive film pattern 201p is formed by etching the semi-transmissive film 201 using this as a mask (see FIG. 12F). Then, the remaining resist pattern 204p is peeled off (see FIG. 12G). In this way, a multi-tone (here, 3) photomask is completed.

  FIG. 12 schematically shows the patterning process, and there are various other types of actual pattern shapes depending on applications.

  In the manufacturing method of the present invention, a transmittance inspection step can be provided after the patterning. This confirms whether or not the correct light transmittance required by the mask user is obtained. If there is any inconvenience, the process returns to the manufacturing process, and if there is no problem, the product can be guaranteed.

  Depending on the desire of the mask user, the numerical value of the light transmittance obtained by the inspection method of the present invention can be supplied as a photomask product in a form associated with the photomask. In other words, even if a photomask product is supplied, it is usually impossible to accurately measure the light transmittance of the fine part. Therefore, the transmittance that is an attribute of the photomask is integrated with the photomask. It is meaningful to attach it. In this case, the supply format may be such that the photomask and the transmittance data are physically integrated, or the distribution is performed individually but the information is associated with each other.

  The user of the photomask can refer to the transmittance data and use the photomask and an exposure machine to transfer the transfer pattern of the photomask to the transfer target to manufacture a desired electronic device. . In this case, various condition parameters applied to the manufacturing process can be set based on the transmittance data.

  In the transmittance measuring apparatus shown in this embodiment, in order to further improve the measurement accuracy, it is preferable to appropriately control the intensity distribution of the test light beam emitted from the light source device.

  For example, in the transmittance measuring apparatus shown in FIG. 1, the intensity distribution of the parallel light beam 111 entering the condenser lens 103 from the collimator lens 102 is a distribution in which the central portion is relatively brighter than the peripheral portion. A light distribution intensity adjusting means can be introduced. An example of the distribution form is a Gaussian distribution.

  In general, when a collimated light beam 111 having a uniform intensity distribution is incident on the condensing lens 103 and condensed on the subject 120, side lobes may be generated around the peak of the collected light. It was confirmed by the inventors (see FIGS. 3A and 3B). In order to accurately measure the transmittance of a minute part, it is necessary to focus the measurement light on the part to be measured, but due to the generation of side lobes, part of the light is also emitted outside the focused spot. Therefore, depending on the size of the fine pattern and the position of the peripheral pattern (for example, the slit width), the side lobe may be incident on a position other than the inspection position of the object 120, and the measurement accuracy decreases due to the protruding light. There is a risk of doing.

  Therefore, it is preferable that the intensity distribution in the parallel light beam 111 entering the condensing optical system is not uniform, and the central portion (near the optical axis) is relatively brighter than the peripheral portion (see FIG. 4). . Thereby, generation | occurrence | production of a side lobe can be suppressed and it becomes possible to measure the transmittance | permeability of a measurement area | region with high precision.

  The type of the light intensity distribution in the parallel light beam 111 is not particularly limited as long as the intensity monotonously decreases toward the peripheral direction compared to the center (near the optical axis). For example, a Gaussian distribution can be used. When the light source is a laser, a Gaussian distribution can be obtained. In the case of other light sources, a similar effect can be obtained by introducing means for adjusting the light distribution.

  FIG. 5 shows a simulation result in which the ratio of the spot light protruding from the fine pattern by the side lobe when the test light beam light intensity distribution is changed is shown. The distribution shape was a Gaussian distribution.

  Specifically, the Gaussian distribution of the parallel light beam 111 from the collimator lens 102 was changed to enter the condensing lens 103, and the ratio of the spot light protruding according to the pattern line width of the subject 120 was measured. As the condensing lens 103, lenses having NAs of 0.4 and 0.65 were used, and light having an evaluation wavelength of 405 nm was used.

FIG. 5A shows a Gaussian distribution of the parallel light beam 111 incident on the condensing lens 103 when the condensing lens 103 with NA of 0.4 is used, the vertical axis indicates the intensity, and the horizontal axis. Indicates a beam cross section (Gaussian distribution width 1 / e ² ) incident on the condenser lens 103.

As described above, the beam diameter of the Gaussian distribution can be defined as a width having an intensity of 1 / e ² (about 13.5%) of a peak value measured on a plane orthogonal to the optical axis. This width (also referred to as “Gaussian distribution NA” or NAg shown in FIG. 5B) is relative to the NA of the condenser lens (also referred to as NAc).
0.4 ≦ NAg / NAc ≦ 0.6
It is preferable that

  For example, based on the NA of the condenser lens, the NA ratio of the Gaussian distribution is obtained from the range of the above formula, and the Gaussian that can be suitably used in the present invention by the ratio with the effective diameter (pupil diameter) of the condenser lens used. The distribution width can be obtained. For example, when the effective diameter of the condensing lens is 1, the diameter of the test light beam (beam cross section) incident on the condensing lens can be in the range of 0.4 to 0.6.

  For example, when a NA 0.4 condensing lens is used and the NA of the Gaussian distribution of the parallel light beam 111 is 0.4, the protruding light is small (0.61%) for a 6 μm wide pattern, but 2 μm. With respect to the width pattern, the protruding light reaches 2.18% (FIG. 5B). On the other hand, even if the same condensing lens is used, if the NA of the Gaussian distribution of the parallel light beam 111 is 0.2 (NAg / NAc = 0.5), the pattern of 6 μm width is 0.0%, 2 μm width. Even the pattern is 0.42%, which improves the measurement accuracy.

  Further, it is preferable that 99.7% or more of the light intensity of the entire test light beam is within the width of the position to be inspected (for example, a semi-transparent portion) (excessive light is 0.3% or less). More preferably, it is 99.9% or more (excessive light 0.1% or less). The light intensity distribution in the beam diameter can be adjusted by using light intensity distribution control means (for example, an apodization filter (see FIG. 7)), selecting the NA of the condenser lens, or a combination thereof.

  As described above, according to the present invention, the signal intensity acquired from the measurement region that the conventional method of acquiring an image using a two-dimensional sensor such as a CCD or CMOS has acquired in the region adjacent to the measurement region. It is possible to obtain an accurate transmittance of the measurement region without causing a problem of fluctuation caused by affecting the change in signal intensity.

  As described above, in the present invention, when measuring the transmittance of a fine pattern, the influence of the transmittance of a pattern existing around the pattern and the diffraction of the inspection light beam by the pattern around the pattern may occur. Therefore, it is possible to measure the transmittance of a fine pattern. Here, the fine pattern in the present invention is effective for measuring the transmittance of a semi-translucent portion having a line width of 0.5 μm or more and 7 μm or less. Furthermore, it is effective for measuring transmittance of a line width of 0.5 μm or more and 5 μm or less, and further a line width of 0.5 μm or more and 3 μm or less.

  In addition, according to the present invention, it has become possible to guarantee quality regarding the film transmittance of a fine pattern of a fine semi-transparent portion of a photomask and a light-shielding portion having the above-described transmittance, which has been impossible in the past. Furthermore, the present invention that can accurately evaluate the film transmittance as a characteristic characteristic of the film without being influenced by the surrounding conditions is also effective in the development of a photomask that is required to be further miniaturized.

  In addition, this invention is not limited to the said embodiment, It can implement by changing suitably. For example, the material, the pattern configuration, the number of members, the size, the processing procedure, and the like in the above embodiment are merely examples, and various modifications can be made within the scope of the effects of the present invention. In addition, various modifications can be made without departing from the scope of the object of the present invention.

DESCRIPTION OF SYMBOLS 101 Light source 102 Collimator lens 103 Condensing lens 104 Incident port 105 Integrating sphere 106 Photo detector 111 Parallel light beam 112 Transmitted light beam 120 Subject 121 Wavelength selection filter 122 Collimator lens 123 Photo detector

Claims (19)

A light source device that emits a test light beam, a condensing optical system that collects the test light beam and guides it to a subject, a light detection device that receives a transmitted light beam that has passed through the subject, and detects the amount of light, and the light A transmittance measuring device having a computing device for obtaining the light transmittance of the subject based on the amount of light detected by the detection device,
The relative positions of the light source device, the condensing optical system, and the subject are adjusted so that the collected test light beam is incident on a subject position to be examined in the vicinity of a beam waist. Transmittance measuring device. The light source device comprises a laser light source;
When the effective diameter of the condensing lens provided in the condensing optical system is 1,
The transmittance measuring apparatus according to claim 1, wherein a diameter of the test light beam incident on the condenser lens is 0.4 or more and 0.6 or less.   The transmittance measuring device according to claim 1, wherein the light detection device includes an integrating sphere provided with a photodetector.   The integrating sphere has an incident port through which a transmitted light beam enters, and the integrating sphere has a port diameter larger than the diameter of the transmitted light beam at a position where the transmitted light beam enters. The transmittance measuring device according to claim 1, wherein the transmittance measuring device is arranged.   The transmittance measuring apparatus according to claim 1, wherein the condensing optical system includes a first collimator lens and a condensing lens.   In order to adjust the relative positions of the light source device, the condensing optical system and the subject in a plane parallel to the main plane of the subject, the light source device and the condensing optical system are moved, or The transmittance measuring apparatus according to claim 1, further comprising a moving device for moving the subject.   The transmittance measuring apparatus according to claim 1, further comprising a second collimator lens that adjusts a diameter of the transmitted light beam between the subject and the light detection apparatus.   8. The condensing optical system includes a light distribution adjusting unit that makes a light intensity distribution in a plane perpendicular to an optical axis of the test light beam larger in a central part than in a peripheral part. The transmittance measuring apparatus according to any one of the above. A transmittance inspection apparatus for measuring a transmittance of a photomask having a transfer pattern formed by patterning an optical film formed on a transparent substrate at a specific inspection position of the transfer pattern,
A light source device that emits a test light beam, a condensing optical system that collects the test light beam and guides it to a photomask, a light detection device that receives a transmitted light beam that has passed through the photomask, and detects the amount of light, and the light An arithmetic unit that obtains light transmittance at the inspection position of the photomask based on the amount of light detected by the detection device;
The relative positions of the light source device, the condensing optical system, and the photomask are adjusted so that the collected test light beam is incident on the inspection position of the photomask near the beam waist. Photomask transmittance inspection device. The light source device comprises a laser light source;
When the effective diameter of the condensing lens provided in the condensing optical system is 1,
10. The photomask transmittance inspection apparatus according to claim 9, wherein a diameter of the test light beam incident on the condenser lens is 0.4 or more and 0.6 or less. In a transmittance inspection method for measuring the transmittance of a photomask having a transfer pattern formed by patterning an optical film formed on a transparent substrate, at a specific inspection position of the transfer pattern,
Condensing the test light beam emitted from the light source device at the inspection position of the photomask, and transmitting the photomask near the beam waist of the test light beam,
The transmitted light beam that diffuses after transmission enters the light detection device,
A transmittance inspection method characterized in that a light transmittance T at the position to be inspected is obtained based on a light quantity L detected by the light detection device.   The photodetector has an integrating sphere equipped with a photodetector inside, and the transmitted light beam is detected by the photodetector in a state where the intensity is uniformed by repeated diffuse reflection within the integrating sphere. The transmittance inspection method according to claim 11.   The transmittance inspection method according to claim 11 or 12, wherein the transfer pattern includes a light-transmitting portion that transmits exposure light and a semi-light-transmitting portion that blocks part of the exposure light.   The transmittance inspection method according to claim 13, wherein the transfer pattern further includes a light shielding portion that substantially shields exposure light.   The photomask is a multi-tone photomask for forming a resist pattern having a plurality of different resist residual values on a resist film formed on a transfer target. The transmittance inspection method according to any one of 14. An arbitrary part on the transparent substrate where the optical film is not formed, or a part where the optical film of the photomask is not formed is used as a reference position.
The test light beam emitted from the light source is condensed at the reference position, and transmitted through the reference position of the transparent substrate or the photomask in the vicinity of the beam waist of the test light beam,
The transmitted light beam that diffuses after transmission is incident on the light detection device,
The light transmittance T at the inspected position of the photomask is calculated using the light amount L0 detected by the light detection device and the light amount L obtained by the transmittance inspection method according to any one of claims 11 to 15. The transmittance inspection method according to claim 11, wherein the transmittance inspection method is obtained. A method for manufacturing a photomask, comprising: preparing a photomask blank having an optical film formed on a transparent substrate; patterning the optical film to form a transfer pattern; and inspecting the transfer pattern In
In the said inspection, the transmittance | permeability inspection method in any one of Claims 11-16 is used, The photomask manufacturing method characterized by the above-mentioned.   18. A pattern transfer method, wherein a photomask manufactured by the manufacturing method according to claim 17 and an exposure apparatus are used to transfer a transfer pattern of the photomask onto a transfer target.   It has the light transmittance T of the to-be-inspected position of the said photomask obtained by the transmittance | permeability inspection method in any one of Claims 11-16 in the state matched with the said photomask, Photomask products.