TW200532164A - Film thickness measuring method and apparatus - Google Patents

Abstract

To provide a film thickness measurement technique which can measure film thickness correctly, even for a transparent film which selectively transmits light of specific wavelength ranges such as a color filter. Theoretical spectral reflectance calculated as the spectral reflectance of a sample, in which a colorless transparent film having predetermined film thickness is formed on a substrate, is acquired a plurality of times for different film thickness. The spectral transmittance of a color filter, which is an object to be measured, is acquired. Concerning the spectral transmittance, a wavelength range providing transmittance of a predetermined value or more is selected as a measurement wavelength range. A plurality of theoretical spectral reflectance calculated for different film thickness are corrected by the spectral transmittance to determine corrected theoretical spectral reflectance. A sample, in which the color filter is formed on a substrate, is irradiated with light, and reflected light from the sample is spectrally separated to measure the spectral reflectance. The measured spectral reflectance is compared to the corrected theoretical spectral reflectance to calculate the film thickness of the color filter.

Description

200532164 IX. Description of the invention: [Technical field to which the invention belongs] The present invention relates to a kind of measurement, such as a transparent film formed on a substrate such as a semiconductor substrate or a glass substrate for a liquid crystal display device, and is particularly selected as a color filter. Film thickness measurement method and device for transparent film thickness that transparently transmits light in a specific wavelength region. [Prior Art] Previously, for example, in Japanese Patent Publication No. 249620 (1994), it has been proposed to use a light interference method to measure the extremely thin photoresist film or silicon oxide film formed on a substrate as described above. The technology of transparent film thickness. In the measurement of the film thickness of the two-light interference method, under the condition that the substrate formed with a transparent film having a film thickness of a specific value d can be radiated by humans, the specified spectral reflectance of the light interference of the thin film is determined. At this time, the film thickness set by the solid thickness of the solid plate at equal intervals is to store the scored light reflectance as a plurality of theoretical spectral reflectances in a memory device such as a memory. : Then, the light is irradiated on the substrate on which the transparent thin ridge of the measurement object is formed, and the spectroscope splits the reflected light reflected from the substrate to measure the spectral reflectance. Thereafter, the difference between the measured spectral reflectance and the above-mentioned theoretical spectral reflectances is calculated. 'The minimum film thickness value is obtained by the curve fitting method previously known, and the obtained thickness value is taken as The film thickness of the transparent film measured. [Problems to be Solved by the Invention] In recent years, with the rapid spread of digital cameras or mobile phones with cameras 97436.doc 200532164, the demand for color CCDs has been increasing. Manufacturing steps for color CCDs: Color filters and light filters of RGB 3 colors are pasted on a silicon wafer in a matrix. Those used in a projector are used to form color filters on a liquid crystal glass substrate. In the step of forming a color filter on such a substrate, it is important to closely manage the thickness of the filter film, and it is required to accurately measure the film thickness of the color filter. However, the color filter only transmits light in a specific wavelength region, for example, in the it shape of the green filter, it transmits only light in a wavelength region of about 480 nm to 600 nm. FIG. 9 is a diagram showing the light transmission characteristics of a color filter. The spectral reflectance (distribution of reflectance with respect to wavelength) obtained when the light is irradiated on the substrate to form a sample having a light-transmitting color filter as shown in the figure becomes as shown in FIG. 10 . Furthermore, in FIG. 1G, the solid reflectance obtained from the substrate on which the color light-emitting sheet is formed is represented by a solid line. Instead of using a color filter for all light in the visible light region, a transparent film (i.e., When the colorless transparent film is used, the spectral reflectance is indicated by a dotted line. What Figure 10 does not do in the case of a colorless transparent film

97436.doc 200532164 The spectral transmittance (distribution of transmittance to wavelength) of the color filter is not shown as a rectangular waveform but as a table-shaped waveform. That is, even in a specific wavelength region where light is transmitted, the transmittance changes analogously near its boundary. Therefore, the reflectance in the wavelength region of the inclined portion of the transmittance distribution becomes lower than the theoretical value. Therefore, if the wavelength region is included in the measurement wavelength region, the reliability of the film thickness measurement will be significantly reduced. For this reason, although the wavelength range of the wavelength region removed from the inclined portion of the transmittance material can be tested, that is, only the wavelength region of the peak top flat portion in the transmittance distribution shown in FIG. 9 is set as the measurement wavelength. In this case, the width of the measurement wavelength region becomes non-narrow to 4q to 50 nm, so there is a concern that the reliability may be reduced in this case. In particular, the thinner the film thickness of the color light-transmitting sheet is, the lower the waveform of the reflectance distribution becomes. The lower the frequency m, the narrower the width of the wavelength range of the epicenter, the narrower the film thickness measurement itself becomes. The present invention was developed based on the above-mentioned subject, and its object is to provide a thickness measurement technology that can accurately measure the thickness of a transparent thin film that can selectively transmit light in a specific wavelength region, such as a color light sheet. [Summary of the Invention] In order to solve the above-mentioned problem, the invention of the applicant is a spectral reflectance obtained by irradiating light to a sample having a transparent film formed on a substrate (a film thickness of the above-mentioned transparent film), a method including: A transmittance obtaining step, which obtains the spectral transmittance of the transparent film; a spectroscopic reflectance measuring step, which irradiates light onto the sample, and separates the reflected light reflected from the sample to measure the spectroscopic reflectance; a calibration step, which Based on 97436.doc 200532164 = first it can be calculated as the formation on the substrate with a specific rate of one == ::, the theoretical spectral reflectance after correction is correct ▲ two: Zhongfu can be measured in the middle of the measurement ... , So that == film thickness of a fixed step film. The object ’s transparency is based on the film_method of the invention claimed in item 2 of the previous two claims. Once the V step is added, the weight corresponding to the above-mentioned spectral transmittance is added. The film thickness of the transparent film of the measurement object is measured by the spectroscopic reflection measurement of the second item of the request item 1 or the item ^ above the threshold. The step range determined to have a specific measurement wavelength region of the above-mentioned spectral transmittance is calculated as the above thickness. In the step, the transparent thin film ::: 4 is issued: 'It is formed by irradiating light on the substrate == measuring method', which includes: the step of obtaining the spectral transmittance, and the second is the spectral transmittance of the transparent thin film. The reflectance measurement step is based on the above sample, and the reflected light reflected from the sample is equal to the spectral reflectance; the correction step is the step of calculating the film thickness in the spectral reflectance measurement step by the spectroscopic transmission y, It compares the theoretical spectral reflectance, which was previously determined as the spectral reflectance of the sample on the substrate = special thick transparent film, and the calibration corrected in the above-mentioned calibration step 97436.doc 2005321 64, real: = reflectance, calculate the film thickness of the transparent thin object to be measured. Measurement of the spectral reflectance obtained from a sample of a thin film: = Thick film thickness measuring device, which includes: First, recorded production: Qiu 7 Excess rate '· 2nd memory mechanism' Theoretical spectroscopic reflectance of its memory 'The theoretical spectroscopic The reflectance is calculated as a transparent meal. The spectroscopic reflectance of a sample with a specific film thickness is cut in the training area. The light source irradiates light to the measurement object n, the image is from the 77 μ material. The correction mechanism will reflect the reflectance and transmittance of the light reflected by the sample of the measurement object; the correction mechanism 'its spectroscopic reflectance based on the above-mentioned theory; and the thickness calculation mechanism, after reading the correct correction in the η mechanism The theoretical spectral reflection and the actual spectral reflectance measured by hunting the above-mentioned spectral reflectance measuring mechanism can be used to calculate the film thickness of the transparent film to be measured. The invention of claim 6 is the film thickness measurement of the invention of claim 5. Device, which stores a plurality of theoretical spectral reflectances of transparent films corresponding to different film thicknesses in the second memory mechanism, and reflects each of the plurality of theoretical spectral reflections in the correction mechanism Multiplying the above-mentioned spectral transmittance to calculate a plurality of corrected theoretical spectral reflectances, and in the film thickness calculating mechanism, the f-values of each of the above-mentioned corrected theoretical spectral reflectances and the actual measured spectral reflectances are calculated so that The film thickness obtained when the plurality of obtained differences are approximately the minimum when the quadratic curve is the film thickness of the transparent film to be measured. The invention of claim 7 is a film thickness measuring device of the invention of claim 6. In the above-mentioned film thickness calculation mechanism, the higher the spectral transmittance becomes 97436.doc 200532164 (the weight reduction is added to the difference between each of the complex number and the measured spectral reflectance, so that the first reflectance is added with weight The difference j indicates that the obtained film thicknesses of the plurality of transparent thin objects to be measured are not included. The value of the film is the invention of item 8, which is a feature of any one of claims 5 to 7. 1 # In addition, it includes a wavelength region selection mechanism for measuring when there is a transmittance above the threshold value of the special optical transmittance at the above-mentioned spectral transmittance, and selecting a region as a film thickness to calculate ❿ and // long regions. The invention of claim 9 is obtained by irradiating light to the sample of the thin film and drying it on the ground. C ... A transparent plate is formed on the soil plate. S: The first memory mechanism, which memorizes the above-mentioned transmittance. Material, ¥ 4 mechanism, its Ji Yi theory spectroscopic reflection ^ ㈣ light reflectance is as a thick transparent film formed on the substrate # 极 从 \ Eight special film, M ^ Do not reflect light reflectance in advance A fixed source, which irradiates light to the sample to be measured. The palladium is irradiated with light from the above-mentioned light source, and the reflected light emitted from the light source is spectroscopically separated to measure the spectrophotometry. Reflectivity; a correction mechanism that calculates the measured birefringence m film thickness from the measured spectral reflectance measured by the above-mentioned spectral reflectance measurement with 4 first transmittance corrections, a comparison ^ described & the actual measured spectral reflectance after the correction is corrected by the positive mechanism Is the light reflectance, so that the film thickness of the transparent film to be measured is calculated; the invention of 1 mile, and the search term H) is based on the continuation of irradiating light to the transparent film ~ & 上 ^ 成 有 * The film thickness measurement device for measuring the above-mentioned film thickness by measuring the spectral reflectance thus obtained The first light source, which irradiates light to the above 97436.doc -10- 200532164 2 film formation surface; the second light source 'which irradiates light to the above sample ~, forming Opposite side; beam splitter, which will be from top

== and transmitted light transmitted through the substrate and the transparent film, *, :: 疋 the spectral transmittance of the transparent film, and will be reflected from the p, column, = and reflected light reflected by the sample to split the light so that It has a two-knife first reflectance; the memory mechanism stores its memory as a transparent film with a specific film thickness of 2 on the substrate. The "differential projection" allows the theoretical spectral reflectance to be obtained in advance; the correction mechanism uses the above-mentioned spectrometer to transmit The above-mentioned spectral transmittance corrects the above-mentioned theoretical spectral reflectance, and the film thickness calculation mechanism, which is compared with the above-mentioned correcting mechanism to correct the theoretical spectral reflectance after being corrected with the above-mentioned spectroscopic mechanism to measure = Measure the spectral reflectance to calculate the film thickness of the transparent film to be measured. 0 [Effect of the invention] According to the invention of claim 1, the spectral transmittance correction is used to compare the thickness of a transparent film with a specific film thickness on the substrate. Spectral reflectance of the sample can be calculated in advance after the theoretical difference between correction and the measured spectral reflectance wire & the thickness of the transparent film of the material. The deviation between the reflectance and the measured spectral reflectance will be eliminated, so that even a transparent thin film that selectively transmits light in the special branch long area like a color light sheet can accurately measure its film thickness. Also according to the invention of claim 2, because The weight corresponding to the spectral transmittance is added, and the theoretical spectral reflectance after correction is compared with the measured spectral reflectance to calculate the film thickness 1 of the transparent thin film to be measured, which can be enhanced. 97436.doc -11-200532164 should be used for spectral transmission The comparison of the reliability of the transmission rate enables a more accurate measurement of the film thickness. According to the invention of the item 3 of the monthly length, the reading having a specific threshold value above the spectral transmittance is selected. The wavelength region of the transmittance of εl is used as the measurement wavelength region. Therefore, the measurement wavelength region can be enlarged to improve the measurement accuracy of the film thickness. According to the invention of the item 4 in °°, it is compared with the case where a transparent film with a specific film thickness is formed on the substrate. Spectral reflectance of the sample, the theoretical spectroscopic reflectance that can be determined in advance, and the corrected spectroscopic reflectance that is corrected by the spectral transmittance In order to calculate the film thickness of the transparent film to be measured, the deviation between the theoretical spectral reflectance and the measured spectral reflectance can be eliminated, so even a transparent film that selectively transmits light in a specific wavelength region like a color filter can be accurately measured. Its film thickness. According to the invention of claim 5, according to the comparison of the spectral reflectance of a sample having a transparent film with a specific film thickness formed on the substrate by spectral transmittance correction, it is different in advance. V + eight m + is The theoretical spectral reflectance of 4 is corrected after the theory = emissivity and measured spectral reflectance 'to calculate the transparency of the measurement object: get =, so the theoretical spectral reflectance and the measured spectral reflectance are the second two "even if the color filter Selective transmission through a specific wave °° 3, 'transparent film can also accurately determine its film thickness.' Also according to the invention of claim 6, multiply each of the multiple by the spectroscopic transmission through the car; ^ ^ Gantun ~ κ varies A plurality of corrected theoretical spectroscopic emissivities are produced, and Ya Qiushi each of these plural corrected post-correction principles # 八 # 应 &# ^ Reflectivity m, x 纟 -the first reflectance of the knife and the measured spectrometry Λ φ The thickness that indicates that the obtained multiple differences are approximated to the second minimum value is the film thickness of the transparent film to be measured. 97436.doc 200532164 Therefore, the deviation between the theoretical spectral reflectance and the measured spectral reflectance will be removed and included. The error in the difference between the two will be greatly reduced, so the accuracy of the quadratic curve approximation is increased, so that even a transparent thin film that selectively transmits light in a specific wavelength region like a color filter can accurately measure its film thickness. In addition, according to the invention of claim 7, the higher the spectral transmittance, the heavier the weight is added to each of the plurality of corrected theoretical spectral reflectances and measured spectral reflectances.

The difference between the emissivity and the minimum film thickness when the difference between the obtained weights with the approximated quadratic curve is approximated as the film thickness of the transparent film to be measured. The higher and the higher the difference, the more the evaluation becomes, so that a more accurate film thickness measurement can be performed. In addition, according to the invention of claim 8, since a transmission wavelength region having a specific threshold value above the spectral transmittance is selected as the measurement wavelength region when the film thickness is calculated, the measurement wavelength region can be enlarged to increase the film thickness. According to the invention of claim 9, because the spectroscopic reflection of a sample formed with a transparent film with a specific film thickness on a substrate is compared, "theoretical divergence material that is different in advance can be corrected by the branch transition"; Measure the spectral reflectance and calculate the film of the transparent film to be measured. Therefore, the difference between the material and the actual age light can be resolved. Therefore, even a transparent film that selectively transmits light with a specific wavelength like a color μ-light sheet can be accurately measured. The thickness of the film is second. The invention of claim 10 is based on the theory that the spectroscopic reflectance of a specific film thickness is formed on the soil plate by comparing the spectral transmittance with the spectral transmittance calibration. Spectral reflection 97436.doc 200532164 The spectroscopic reflectance and the measured spectroscopic reflectance are calculated, and the film thickness of the transparent film to be measured is calculated. The deviation between the emissivity and the measured spectral reflectance will be eliminated, so even a transparent film that selectively transmits light in a specific wavelength region like a color filter can accurately measure its thickness. [Embodiment] Hereinafter, referring to the drawings An embodiment of the present invention will be described in detail. '≪ 1 · 1 embodiment > Fig. 1 is a diagram showing a configuration of a film thickness measuring device of the present invention. The film thickness measuring device includes a first illumination optical system 10 The second illumination optical system 20 and the imaging optical system 30. The first illumination optical system 10 includes a halogen lamp 11 that emits white light and an illumination lens 12. The illumination lens 12 is constituted by a combination of, for example, a condenser, and an omitted figure is attached to the condenser. The field of view diaphragm, etc. The light emitted from the halogen lamp 11 is incident on the imaging optical system through the illumination lens 12. The imaging optical system 30 includes an objective lens 31, a half mirror 32, and an imaging lens 33. From the i-th illumination optical system 1〇 The illumination light looks like a half mirror

Is irradiated and irradiated onto the sample 丨 placed on the sample port A and the silver σ port table 5 through the objective lens 31. In addition, the sample 1 is a color filter formed on a semiconductor substrate or a liquid crystal substrate, and a glass substrate such as a glass substrate, which is a device for colored display, is formed on a substrate every day. In other words, light can be emitted from the first illumination optics 蛴 旧 0 old & Yu 先, · 10 makeup first to the film forming surface of sample 1. The sample stage 5 has an opening mounting stage at the center. An XY drive mechanism (not shown) is attached to the sample stage 5, and the sample 1 is placed and moved in the X direction and the Y direction in the horizontal plane. In addition, the sample stage 5 may be a center 97436.doc -14- 200532164. The center 4 has an opening and can mount a sample! Alternatively, it may be, for example, a frame that holds the peripheral portion of the sample 1. On the other hand, the second illumination optical system 20 is disposed on the opposite side from the imaging optical system 30 without the sample stage 5. The second illumination optical system 20 includes a tooth lamp 21 and an illumination lens 22 which emit white light. It is preferable that the spectral characteristics of the light emitted by the halogen lamp are the same as those of the illuminator lamp 11. Alternatively, one element lamp may be used to form the element lamps 11 and 21, and the light is guided by an optical fiber or the like. In addition, the illumination lens 22 is a lens system having a focusing function. The light emitted from the prime lamp 21 is condensed through the makeup lens 22 and is irradiated to the back of the sample 丨 through the opening of the sample stage 5, that is, the same as the sample 1 The surface on the opposite side of the film formation surface. The light irradiated from the first illumination optical system 10 and reflected on the sample 丨 and the light irradiated from the second illumination optical system 20 and transmitted through the sample 1 are collected by the objective lens 31, the half mirror 32, and the imaging lens 33 to be focused on the imaging A specific position on the optical axis of the optical system 30. The spectroscopic unit 40 is arranged such that the entrance pinhole of the spectroscopic unit 40 is located near the light-condensing position. The spectroscopic unit 40 includes a concave diffraction grating 41 that splits incident light and a light detection 42 that detects a spectral spectrum of the diffraction light diffracted by the concave diffraction grating 41. The photodetector 42 includes, for example, a photodiode array or ccd. Thereby, the light condensed by the imaging optical system 30 and incident on the spectroscopic unit 40 is split by the concave diffraction grating 41, and a signal corresponding to the spectroscopic spectrum of the light is transmitted from the photodetector 42 to the arithmetic unit 50. FIG. 2 is a block diagram showing the configuration of the arithmetic unit 50. The calculation unit 50 calculates the film thickness of the color filter of the sample 1 based on the spectral spectrum information received from the spectroscopic unit 40. The arithmetic unit 50 has the same hardware configuration as a general computer, and 97436.doc -15- 200532164 includes a CPU 51 for performing various arithmetic processes, a ROM 52 as read-only memory for storing basic programs and the like, and a work area for the CPU 51 RAM53, which is a freely readable and writable memory, and disk 54 for storing programs or various data. The CPU 51 is connected to a keyboard 60, a CRT 61, a printer 62, and the photodetector 42 described above via an input / output interface (not shown). The operator of the film thickness measuring device can input various instructions or parameters from the keyboard 6G to the calculation section 50, and can confirm the calculations output from the CRT 61 or the printer

result. Further, the halogen lamp U and the halogen lamp 12 are respectively provided with lamp power sources: the sample stage 5 is provided with an XY driving circuit (both are not shown), and the computing unit 50iCpu5i is also electrically connected to these. Furthermore, the correction section & film thickness calculation section 56 and the measurement wavelength region 敎 section shown in FIG. 2 are processing sections which are realized by implementing a special processing program by cpu5i. Details of the processing are described below. This will be described further.

Next, the processing steps of the 臈 thickness measuring method of the present invention are added. Fig. 3 shows the flow of the processing steps of the film thickness measuring method of the present invention. Here, 'the spectroscopic reflectance measurement obtained by irradiating light to the test is described. The step of changing the thickness of the color phosphor film, the above-mentioned sample ^ is formed on the substrate with a green color light film as a film. In addition, of course, it is not limited to, and = :, the film thickness of other colors such as phosphor film or red phosphor film can also be measured in the same procedure. First, a transparent step (si) is obtained in which the spectral reflectance of a sample formed on a substrate is set to a thickness. The theoretical spectral reflectance is f + reflection ^ Shi Xiba ^ Calculate the spectral reflectance of the article under the following conditions, and this condition is formed with the 97436.doc -16- 200532164 color filter as the measurement object A bright film having a specific film thickness d is formed on the same substrate as the substrate, and white light is incident on the colorless transparent film from the (lighting optical system 10). Furthermore, the so-called "reflectance" in this specification It is the ratio of the reflection intensity to the reflection intensity when the transparent film is not strictly formed on the substrate (the film thickness is zero), that is, the relative reflectance.: The spectroscopic reflectance is based on the colorless transparent films with different film thicknesses. Calculate 'these colorless transparent films with different film thicknesses d are within a fixed range corresponding to the film thickness of the color filter to be measured (for example, if the film thickness of the beta color calender of the measurement target is hundreds of coffees) The range is from 100μ to 丨 _c) is set at equal intervals (for example, 10 nm pitch). Because light interference occurs in the transparent film, the reflectance of the wavelengths where the light strengthens with each other becomes higher, and the mutual reflection decreases. The wavelength reflectance is reduced. The conditions for generating light interference are determined by the film thickness of the transparent film, so the pattern of the spectral reflectance is different based on the film thickness theory. Therefore, 'the theoretical spectral reflectance can be based on the light interference conditions for different film thicknesses. Figure 4 is a graph illustrating the theoretical spectral reflectance of colorless transparent films with different film thicknesses. Figure 4 (a) is the theoretical spectral reflectance of transparent films with thicker films, and (b) is the The theoretical spectral reflectance of a transparent film with a thinner film thickness. As shown in Figure 4, the thinner the film thickness, the lower the pattern period of the theoretical spectral reflectance. That is, the peaks and valleys of the theoretical spectral reflectance in a fixed wavelength region will decrease. Data corresponding to the theoretical spectral reflectance of such transparent films with different film thicknesses calculated in advance will be stored in the magnetic disk 54. Next, the process proceeds to step S2 to obtain the knife light transmittance of the color filter as the measurement target. Color filter The spectral transmittance of the film can also be measured directly in the film thickness measurement of 97436.doc 200532164 set in Figure 1, or it can also be measured in advance. That is, it can transmit the entire area of visible light. When a color filter is formed on a glass substrate, directly measure the spectral transmittance of 20 using the second illumination optical system, and use a pre-measurement when a color filter is formed on a silicon substrate that is opaque to visible light. When the color filter is formed on the glass substrate, the substrate itself can transmit light directly, so the spectral transmittance can be measured directly. At this time, the sample is irradiated from the second illumination optical system 20 and transmitted through the sample. The substrate and the color filter) are focused by the imaging optical system 30, and the light is split by the spectroscopic unit 40 to determine the spectral transmittance of the color filter. Measured by the spectroscopic unit 40 The spectral transmittance will be transmitted to the calculation unit 50 and stored in the magnetic disk 54. On the other hand, when a color filter is formed on a silicon substrate, the substrate itself cannot transmit light, so the spectral transmittance cannot be directly measured. Use a transparent substrate (such as a glass substrate) formed with a color filter that has the same material and the same thickness as the color filter to be measured. ) Previously measured spectral transmittance. The film thickness measuring device of this embodiment can also be used to measure the spectral transmittance of a color filter and a light sheet using such a sample for a vision device ', or other devices for measuring the spectral transmittance can be used. The measurement method is the same as the above-mentioned direct measurement. The obtained spectral transmittance data is input to the calculation unit 50 through a specific communication circuit or recording medium, and is stored in the magnetic disk 54 °. Furthermore, in this embodiment, a plurality of data are used. Both the theoretical spectral reflectance data and the spectral transmittance data are stored in the magnetic disk 54, and either of them can be stored in a different memory device (such as RAM53). 97436.doc -18- 200532164 Fig. 5 is a graph showing the spectral transmittance of an example of a non-shirt colored calender. The color filter basically has the characteristic of selectively transmitting only light in a specific wavelength region, as shown in FIG. 5; in the case of a black shirt color filter, it transmits light in a wavelength region of about 48 nms to 600 cong. Even in this wavelength region, it is almost completely transmitted (transmittance is about free.) The width of the wavelength region of the flat portion of the peak of light is 40 planes, and the light transmission is attenuated (the transmittance is between 0% and 10%. 〇% 之 推移) the inclined portion. In addition, the spectral transmittance in this specification is a relative value when the maximum value in the measurement range of minutes = is set to 100%. When the film thickness is measured in a wavelength region where the light transmittance of the inclined portion is relatively low, the deviation between the theoretical spectral reflectance and the actual spectral reflectance will increase, and this will be the cause of poor heart & In the present invention, although the deviation is reduced by the method described below, it is preferable that the measurement should be performed in a wavelength region with a large transmittance as much as possible even in such a treatment. For this reason, in the spectral transmittance shown in Fig. 5, a wavelength region having a transmittance of a fixed threshold value or more is selected as a measurement wavelength region for film thickness measurement (step S3). / The selection of the 疋 wavelength region can also be performed manually by the operator of the film thickness measuring device, or it can be automatically operated by the device based on a preset threshold. In the case of manual operation, the operator observes the spectral transmittance shown in CRT 61 as shown in Figure 5 and selects an appropriate measurement wavelength region, and enters the wavelength region from the keyboard ⑼. In this case, the measurement can be made by considering the balance of the wavelength range and the transmittance. On the other hand, in the case of automatic selection, the chirped-wavelength region selection unit 57 obtains transmittance data that is greater than a predetermined threshold from the data of the spectral transmittance in FIG. 5, and selects the corresponding wavelength region as the measurement Wavelength region. In addition, the operator can observe 97436.doc -19- 200532164 to observe the spectral transmittance of CRT61, as shown in FIG. 5, and input the appropriate threshold value from the keyboard 60 to measure the wavelength region selection unit 57 corresponding to the ^ The wavelength region of the transmittance data above the limit is used as the measurement wavelength region. The greater the width of the measurement wavelength range, the higher the accuracy of the theoretical difference between the emissivity and the emissivity. On the other hand, if the transmission =, the error will increase. To this end, regardless of whether manual or automatic is selected: ㈣ΓΙ selects the measurement wavelength region in consideration of these balances. In this implementation, the measurement wavelength region selection unit 57 automatically selects the measurement wavelength region based on the threshold value received in advance, and selects a wavelength region with a transmittance of 70% or more (approximately 50%) in the spectral transmittance of FIG. 5. ⑽ to ㈣ The measurement of the film thickness in Zhuxian County is based on the measurement of the film thickness. The wavelength range of 波长 ± is used to capture the wavelength & domain. Furthermore, the selected wavelength range of 暂时 is temporarily stored in, for example, RAM 53. The next step is to proceed to step S4 by The specular reflectance of the test material 1 of the film thickness measuring device shown in FIG. 1 at this time. Since the first shot on the sample! Above: The reflected light from the other side is illuminated by the imaging optical system 30. The spectroscopic unit 40 splits the light, thereby measuring the spectroscopic reflectance of the sample. The measured spectroscopic transmittance measured by the spectroscopic unit 40 is transmitted to the computing unit 50. The dry elbow is transported: the measured spectroscopic reflection indicating the sample! An example of the rate. In the actual measurement shot two: the reflection value caused by the light interference at the transparent film appears. The transparent film of the right test m is not colored. The measured spectral reflectance should also appear as shown in Figure 4. Two = rate Like The peaks are repeated. However, since the color phosphor film only passes light in the special wavelength region, the reflectance peak appears only in the specific 97436.doc -20-200532164 wavelength region shown in FIG. 6. Also, even for a specific wavelength In the region where the transmittance is almost 100%, the same reflectance characteristics as the theoretical spectral reflectance can be obtained. However, in other wavelength regions, the transmittance decreases with the decrease of the theoretical spectral reflectance and the measured spectral reflectance. The measured spectral reflectance of sample 1 which deviates from the general rule, is temporarily stored in, for example, RAM 53. Alas, in this embodiment, the measured spectral reflectance is measured through a wider wavelength region of the entire area of visible light, but it may be only The measured spectral reflectance is measured based on the measurement wavelength region selected based on the aforementioned spectral transmittance. Next, the process proceeds to step S5 to correct the theoretical spectral reflectance stored in the magnetic disk 54 by the spectral transmittance. At this time, based on the aforementioned spectral transmittance The calibration is performed within the selected measurement wavelength range. Χ, a plurality of principles for each transparent film corresponding to a different film thickness On the implementation of correction of the spectral reflectance. Specifically, the correction unit 55 corrects the theoretical spectral reflectance according to the following formula 1. [Equation 1] R, (X) = T (X) -R (X) , I1 (λ) is the value of the theoretical spectral reflectance at the wavelength λ, τ (λ) is the value of the spectral transmittance at the wavelength input (strictly speaking, the transmittance is plotted as the normalized value), R⑻ The value of the theoretical spectral reflectance at the wavelength after calibration is m 卩. The theoretical spectral reflectance r 反射 is multiplied by the spectral transmittance τ (λ) to calculate the theoretical theoretical spectral reflectance rw after correction. Figure 7 is a summary A graph illustrating the correction of the theoretical spectral reflectance derived from the spectral transmittance. The solid line in the upper side of the same figure indicates the theoretical spectral reflectance before correction, and the dashed line indicates the theoretical spectral reflectance after correction. As mentioned above, 97436.doc -21-200532164 has a peak top flat portion with almost the transmittance and a slant portion whose transmittance shifts between 0/0 and 100% in the knife light transmittance, corresponding to the flat top. The theoretical spectral reflectance of the wavelength region is approximately the same as the theoretical spectral reflectance after correction. On the other hand, in the wavelength region of the inclined portion corresponding to the spectral transmittance, the value of the theoretical spectral reflectance corresponding to the spectral transmittance after correction will also be lower than that before the correction. The correction section 55 performs such correction on each of a plurality of theoretical spectral reflectances obtained corresponding to transparent film with different film thicknesses.

= Theoretical spectroscopic reflectance after correction. Furthermore, in this embodiment, a wavelength region having a transmittance of 70% or more in the spectral transmittance is selected as a measurement wavelength region for film thickness measurement. Therefore, the maximum value of the reduction rate due to correction is about 30%. . Next, the process proceeds to step S6, and the film thickness calculating unit 56 calculates the film thickness of the color f-light sheet to be measured by comparing the corrected theoretical second reflectance with the Δ spectroscopic reflectance. Specifically, first, the film thickness calculation unit 56 calculates the transmission of the measured spectral reflectance and the thickness of the film according to the difference in the next step.

The difference D (d) of the corrected theoretical spectral reflectance of the thin film. [Equation 2]

(Named) =] * {11 '(in, d) -S〇)} 2cR; # In Formula 2, r (λ, d) is the theoretical spectral reflection of the wavelength of the transparent film with a thickness of d. The value of the ratio, δ (λ) is the measured spectral reflectance at the wavelength λ, and the value of the ratio. Furthermore, the integration range of the heterogeneous equation 2 is based on the above-mentioned spectral transmittance; the measurement wavelength region determined by the step S3. Alternatively, instead of calculating the square of the difference between y (in,) and (λ), an absolute value may be calculated. The film thickness calculating unit 56 differs from the corrected theoretical spectroscopic 97436.doc -22- 200532164 of each of the transparent films of different film thicknesses according to the formula 2 and calculates the difference between the reflectance and the measured spectral reflectance. Then, the film thickness calculation unit 56 applies a curve fitting method to the plurality of difference values obtained in the above manner to obtain a film thickness value with the smallest difference value, and sets the film thickness value β as the color filter of the measurement target. The film thickness of the sheet. Specifically, the film thickness calculation unit 56 makes the difference between the measured spectral reflectance and the corrected theoretical spectral reflectance of each transparent film with different film thicknesses approximate the minimum film thickness value when the quadratic curve is approximated. The thickness of the target color filter is measured. FIG. 8 is a diagram conceptually showing an approximate quadratic curve for film thickness measurement. In the example of FIG. 8, the difference D (di) to 〇 (heart) of the measured spectral reflectance and the theoretical spectral reflectance of a plurality of transparent films with a thickness of seven to & From this, the minimum difference Dmin is obtained, and the correspondence is calculated. Take the film thickness value 1 with a small difference Dmin. Then, the film thickness calculation section% sets the film thickness value dx as the film thickness of the color filter to be measured. The calculated film thickness values are, 疋, Ό, and Ό are shown in the CRT 61 and can be output from the printer μ if necessary. As described above in the first embodiment, the theoretical spectral reflectance and the measured spectral reflectance are compared by correcting the theoretical spectral reflectance of the theoretical optical reflectance by correcting the spectral transmittance and measuring the film thickness of the target color filter. . As mentioned above, the color filter only selects the light that transmits through a specific wavelength region. If the film thickness is the same, the theoretical spectral splitting is performed in the wavelength region of the flat top of the peak with a transmittance of almost 100%. The reflectance is consistent with the measured spectral reflectance. However, in the wavelength region other than I 随着, as the transmittance decreases, the theoretical spectral reflectance and measured spectral reflectance divergence will increase. The difference between the theoretical spectral reflectance and the measured spectral reflectance in the wavelength region with a transmittance of almost 100% at the peak peak level of 1 ° 卩 will become the correct one. 'As the transmittance decreases, the The difference between the theoretical spectral reflectance and the measured spectral reflectance at this wavelength region will contain more errors and differences. Accordingly, in order to reduce such an error, it is preferable to set only a peak top flat portion of the transmittance as much as possible to the measurement wavelength region. On the other hand, in order to improve the accuracy of the curve fitting method used for film thickness calculation, it is better to calculate the difference between the theoretical spectral reflectance and the actual measured spectral reflectance in such a way that the measurement wavelength region is enlarged as much as possible. Especially in the case of thin film thickness of the color crossing sheet, the spectral reflectance waveform is smoother (low-frequency waveform), so the processing of expanding the measurement wavelength region as much as possible is to improve the accuracy of the curve fitting method # key point. In the i-th embodiment, 'the theoretical spectral reflectance is corrected by the spectral transmittance', thereby satisfying two contradictory requirements similar to those described above. That is, if the correction of the theoretical spectral reflectance times the spectral transmittance is implemented, the deviation between the theoretical spectral reflectance and the measured spectral reflectance in the wavelength region where the correction is performed can be removed, and the error included in the difference between the two will be greatly increased. The measurement wavelength region can be set in a wide manner so as to exceed the flat portion of the peak top. As a result, the accuracy of the curve fitting method used to calculate the film thickness will be higher, so more accurate film thickness measurement can be performed. If this situation is explained in more detail, it is possible to accurately measure the thickness of a transparent film that selectively transmits light in a specific wavelength region like a color phosphor, by using a theoretical spectral reflectance with a spectral transmittance added. In particular, even when the film thickness of the color filter becomes thin, it is possible to widely set the 敎 · wavelength region ', so that it is possible to improve the precision of the m-line fitting method for film thickness calculation. < 2. Second Embodiment > Another 97436.doc -24- 200532164 Next, a second embodiment of the present invention will be described. The device configuration of the film thickness measuring device of the second embodiment is the same as that of the p embodiment shown in Fig. 2; the processing steps of the film thickness measurement method are also substantially the same as those of the second embodiment. The difference between the second embodiment and the second embodiment is that the weight corresponding to the spectral transmittance is added to the difference between the theoretical spectral reflectance and the measured spectral reflectance when calculating the film thickness of the color filter. In the second embodiment, when measuring the film thickness of the color doped sheet, the same processing as that of steps 81 to 85 in Fig. 3 described above is performed. Then, the process proceeds to step S6, and the film thickness tout # 56 is calculated by comparing the theoretical spectral reflectance after the correction with the measured spectral reflectance 'to calculate the film thickness of the color filter to be measured. At this time, a weight corresponding to the spectral transmittance is added. Specifically, the film thickness calculation unit 56 differs from the measured spectral reflectance based on the following Equation 3 and the difference D, ⑷ with the weight of the theoretical spectral reflectance after correction of the transparent film with respect to the film thickness d. [Equation 3] D ^ d) = iT (X) {RXX, d) «S (\)} 2d \ In # 3, R (λ 'd) is at the wavelength of the transparent thin film with the thickness d. The corrected theoretical reflectance value of s, s (x) is the measured spectral reflectance value of wavelength 4 'τ (λ) is the spectral transmittance value of wavelength 4. In addition, as described above, the knife light transmittance τ (λ) is a value normalized by setting 100% of the transmittance to i. The integral range of the equation 3 is the measurement wavelength region in step S3. · According to Equation 3, the film thickness calculation unit _ points has the following values, which are about to be corrected. · The squared value of the difference between the R-blade light reflectance R (λ 'd) and the measured specular reflectance ⑽) is multiplied by the knife light transmission. Value of the rate τ (λ). The spectral transmittance τ (χ) is to set the transmittance to 97436.doc • 25- 200532164 as 100%! And the normalized value, so in Equation 3, the higher the spectral transmittance T (λ), the heavier the weight will be added to the corrected theoretical spectral reflectance (d), and only the difference between the spectral reflectance S⑻ will be measured. . It can be considered that the difference in the wavelength region corresponding to the flat portion of the peak top where the transmittance is almost the same is better than the difference in the wavelength region corresponding to the inclined portion where the transmittance shifts between running. In addition, the 'film thickness calculation unit 56 calculates the difference between the weights of the theoretical spectral reflectance and the measured spectral reflectance of each transparent film with different film thicknesses based on Equation 3 in the same manner as in the above-mentioned embodiment. The film thickness calculation unit 56 ′ uses the curve fitting method to obtain the film thickness value with the smallest difference from the plurality of weighted values obtained in the manner described above, and sets the thickness value as the color filter to be measured. The film thickness of the sheet is the same as above! The same applies to the embodiment. The film thickness of the color filter to be measured is a film thickness value obtained when a plurality of the obtained weight differences are close to the minimum value when the quadratic curve is obtained. & In the second embodiment, the higher the spectral transmittance, the heavier the weight is added to the difference between the corrected theoretical spectral reflectance and the measured spectral reflectance. If processed as in the first embodiment, the difference between the theoretical spectral reflectance and the measured spectral reflectance contained in the wavelength region where the transmittance is low can be greatly reduced in the spectral transmittance. However, even this is still the case. The reliability of the difference between the theoretical branched emissivity and the measured spectral reflectance at the wavelength region of the flat portion of the ridge top with a transmittance of almost 100% is high. Therefore, in the second embodiment, such a difference with higher reliability can be evaluated higher, and the lower the transmittance, the lower the difference between reliability and lower evaluation. If it is processed as in the second embodiment, the accuracy of the curve fitting method used for film thickness calculation will be further improved, even if it is selectively transmitted through a specific wavelength region, as in the case of color cross light 7 97436.doc -26- 200532164. Its film thickness. The moon can also be more accurate < 3 · Modifications > The embodiment of the present invention has been described, but the present invention is not limited to the above-mentioned examples. For example, in each of the above two theoretical spectral corrections by the spectral transmittance correction, the following is: Instead of this, the measured optical transmittance correction is used to measure the measured reflectance ^ first, but can also be used instead of, or the knife light reflectance. The two correcting sections 55 of the body remove the measured spectral reflectances' by the splitting pass ratio, thereby measuring the actual spectral reflectances after the difference. It is said that the eight films & "t film; π out section 56 comparison principle = reflectance and the measured spectral reflectance after correction, from which the calculation becomes: = film thickness of the color phosphor film. The comparison method at this time is the same as above Implementation: Same. Even if processed in this way, the error of the difference between the theoretical spectral reflectance and the measured spectral reflectance in the wavelength region where the correction is performed will reduce the amplitude, and the accuracy of the curve fitting method used to calculate the film thickness will remain Therefore, a more accurate measurement of the film thickness can be implemented. That is, as the transmittance of the color phosphor film decreases, the deviation between the theoretical spectral reflectance and the measured spectral reflectance that deviates becomes larger, and the theoretical spectral reflectance is corrected by the spectral transmittance. Any of the reflectance or the measured spectral reflectance, the error contained in the difference between the theoretical spectral reflectance and the measured spectral reflectance will be reduced. Therefore, even as a color data sheet, the transparency of light that selectively transmits through a specific wavelength region is transparent. The thickness of the thin film can also be measured accurately. In the above embodiment, it is assumed that the theoretical spectral reflectance of the spectral transmittance disk is obtained and corrected, however, if the color is known, Type of film: and the spectral transmittance and theoretical spectral reflectance have been obtained, the 97476.doc > 27- 200532164 memory can also be memorized by the spectral transmittance, the theoretical theoretical specular reflection The rate is on the magnetic disk 54. In the above embodiment, the film thickness of the color filter and the light sheet is measured, but it is not limited to the color filter and the light sheet. Even if the transmittance is measured in the visible light region, the transmittance is non-uniform. The technology of the present invention can also be used in the case of the film thickness of a transparent thin film. [Industrial Applicability] As a practical example of the present invention, the color filter formed on the half-half substrate is measured during the manufacturing steps of the color CCD. The processing of the film thickness of the sheet or the processing of the film thickness of the color filter formed on the liquid crystal glass substrate in the manufacturing process of the projector. [Brief Description of the Drawings] FIG. 1 shows a film thickness measuring device of the present invention. Figure 2 is a block diagram showing the structure of the calculation section of the film thickness measuring device of Figure 丨 Figure 3 is a flowchart showing the processing steps of the film thickness measuring method of the present invention. Figures 4 (a) to (b) are Instantiating different films A graph showing the theoretical spectral reflectance of a thick transparent film. Figure 5 is a graph illustrating the spectral transmittance of a color filter. Figure 6 is an example of the actual spectral reflectance of a sample to be measured. Figure 7 A conceptual illustration of the correction of the theoretical spectral reflectance derived from the spectral transmittance. Figure 8 is a conceptual representation of an approximate quadratic curve for film thickness measurement. 97436.doc -28-200532164 Figure 9 shows A diagram showing the light transmission characteristics of a color filter. Fig. 10 is a diagram showing the spectral reflectance obtained from a substrate on which the color filter of Fig. 9 is formed. [Description of Symbols of Main Components] 1 Sample 5 Sample Stage 10 First Illumination optical system 11, 21 Halogen lamp 20 Second illumination optical system 30 Imaging optical system 32 Half mirror 40 Spectral unit 50 Calculation section 54 Disk 55 Calibration section 56 Film thickness calculation section 57 Measurement wavelength region selection section 97436.doc-29 -

Claims (1)

200532164 10. Scope of application for patents ... The K plate method is characterized in that it is the spectral reflectance obtained from irradiating light to a base transparent sample with a transparent film, and measuring the film thickness of the above transparent cymbal film, and includes The light-transmittance obtaining step obtains the spectroscopic and spectral reflectance measurement steps of the transparent film, which irradiates light onto the sample, and spectroscopically reflects the reflected light reflected from the upper phase material to measure the spectral reflectance. The theoretical spectral reflectance corrected in advance as the spectral reflectance of a sample of a transparent film having a specific film thickness on the substrate is corrected from the above spectral transmittance; and 2.3.4. The thickness calculation step, which is compared with the above The corrected light reflectance after correction in the correction step is calculated as "1 knife" and "reflectance" measured in the above-mentioned spectral reflectance measurement step to calculate the film thickness of the transparent film to be measured. For the method for measuring the film thickness of item 1, Wherein, the above-mentioned thickness calculation step is added with a phase value corresponding to the above-mentioned > & ϋ μ $ > p # ', first edge transmittance, and comparing the corrected emissivity Based on the above-mentioned measured spectral reflectance, the film thickness of the transparent 4 film to be measured is calculated. If the method of the film thickness of the item 请求 is requested, it further includes the selection of the above: :: transmission = wavelength region with a transmittance above a certain threshold value " A method for measuring a wavelength region in the above-mentioned skin thickness difference step. A method for measuring a film thickness, characterized in that it is a spectral reflectance obtained by irradiating light to a sample having a transparent film formed on a substrate, and measuring the transparency The thickness of the thin film includes: 97436.doc 200532164 Spectral transmittance obtaining step, which obtains the spectral transmittance of the transparent film; Spectral reflectance measuring step, which irradiates light onto the sample, and reflects from the sample The spectroscopic reflectance is measured by reflecting the reflected light; the positive step 'corrects the measured spectral reflectance measured by the above-mentioned spectral reflectance measuring step by the above-mentioned spectral transmittance; and the film thickness difference step, which is compared as forming on the substrate Spectral reflectance of a sample with a specific thickness of a transparent film After measuring the spectral reflectance after the correction in the above-mentioned correction step, calculate the film thickness of the transparent film to be measured. 5. A film thickness measuring device, which is characterized in that it irradiates light to a transparent film formed on the substrate Spectral reflectance obtained from the sample, the thickness of the transparent film is measured, and includes: the first hidden mechanism, which § recalls the spectral transmittance of the transparent film; θ second memory mechanism, whose memory is used as the substrate A theoretical spectroscopic reflectance calculated in advance on a spectroscopic reflectance of a sample having a transparent film with a specific film thickness is formed thereon; a light source that irradiates light to a sample to be measured; # a light reflectance measuring mechanism that is irradiated from the light source Light, and spectroscopic reflection is measured by splitting the reflected light reflected from the sample of the measuring object :: mechanism 'which corrects the above-mentioned theoretical spectral reflectance by the above-mentioned spectral transmittance; and the film thickness calculation mechanism, bean ratio / ratio After correction by the above-mentioned correction mechanism 97436.doc 200532164 6 .: Light reflectance and continuous measurement by the above-mentioned spectral reflectance measurement mechanism Light reflectance, calculates the thickness of the transparent film of the object to be measured. For example, the film thickness measuring device of claim 5, wherein the second memory mechanism stores a number of theoretical spectral reflectances corresponding to different film thicknesses; # @ γ J Multiplying each of the plurality of theoretical spectral reflectances by the above-mentioned spectral transmittance to calculate a plurality of corrected theoretical spectral reflectances; J The film thickness calculation mechanism obtains each of the plurality of corrected theoretical spectral reflectances = and each of the above-mentioned measured spectral reflections The film thickness of the transparent film to be measured is the film thickness value that represents the minimum value when the obtained plural differences approximate the quadratic curve. For example, the film thickness measuring device according to claim 6, wherein the film thickness calculation mechanism performs the addition of H to the above-mentioned spectral transmittance for the difference between each of the corrected theoretical spectral reflectances and the measured spectral reflectance. 'Asian' represents the minimum value of 8. 9 · _thickness when the obtained multiple weighted differences approximate the quadratic curve as the film thickness of the transparent membrane of the object. For example, if any of the items 5 to 7 is included in the measurement device, it further includes the measurement of the film thickness when the 2 regions having the above-mentioned spectral transmittance having a specific threshold value or higher are selected as the film thickness calculation. The fixed mechanism of the wavelength region. A film thickness measuring device is specifically designed to measure the film thickness of the above-mentioned transparent thin film, including the spectral reflectance obtained by irradiating light onto the substrate ^: a sample with a transparent tincture, and including · 97436.doc 200532164 The first memory mechanism memorizes the spectral transmittance of the transparent film; the second memory mechanism memorizes the spectroscopic reflectance of a sample having a specific film thickness of a transparent H film formed on the substrate. Theoretical spectral reflectance; light source, which irradiates light to the sample to be measured; a spectroscopic reflectance measuring mechanism, irradiates light from the light source, and spectrophotometrically measures the reflected light reflected from the 5th material of the target Spectral reflection A correction mechanism that corrects the spectral reflectance determined by the spectral reflectance measurement mechanism described above with the spectral transmittance; and a film thickness calculation mechanism that measures only the light reflectance of the knife after the correction corrected by the correction mechanism described above Calculate the film thickness of the transparent thin film to be measured with the theoretical spectral reflectance. ίο -A diameter ... thickness device, characterized in that it is a spectral reflectance obtained from irradiating light to a sample on which a transparent film is formed on the board, and the thickness of the above-mentioned transparent thin film is measured, and includes: a first light source, thallium radiation Light is applied to the film formation surface of the sample; a second light source irradiates light to a surface opposite to the film formation surface of the sample; a spectroscopic mechanism, i will be white, μ, and +. ,,, / ,, and the second light source is irradiated and transmitted through the substrate Π Γ Γ Γ: the spectroscopic transmission of the light is measured to determine the second and the opposite of the transparent film: '' and will be irradiated from the first light source and borrowed The spectroscopic reflectance is measured from the above-mentioned test by spectroscopic reflection of light; the L mechanism is a theory that is calculated in advance as the spectroscopic reflectance of a sample having a transparent film with a specific film thickness of 97436.doc 200532164 formed on a substrate. Spectral reflectance; a correction mechanism that corrects the theoretical spectral reflectance by using the spectroscopic transmittance measured by the spectroscopic mechanism; and a mechanism that compares the correction with the correction by the correction mechanism: Based on the actual spectral reflectance measured by the spectroscopic mechanism, the film thickness of the transparent thin film to be measured is calculated. 97436.doc