JP5281335B2 - Film thickness measuring apparatus and film thickness measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film thickness measuring method capable of improving the reliability of measuring. <P>SOLUTION: The film thickness measuring method includes: irradiating a light to a substrate to be measured; spectroscopically separate the reflected light from the substrate to be measured; detecting the spectroscopically separated light and outputting a signal according to the intensity of the detected light; calculating the thickness of a thin film based on the error between the output signal and the theoretical waveform; grouping the measurement points; among the measured data at a plurality of the measurement points grouped as the same group, determining a part of them as a measurement error according to at least one side of the thickness of the thin film and the error; and conducting the statistical processing by removing the measurement data determined to be the measurement error from the statistical data for the statistical processing. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a film thickness measuring device and a film thickness measuring method, and more particularly to an optical interference type film thickness measuring device and a film thickness measuring method.

  In recent years, display devices using liquid crystals have been actively applied to products that take advantage of low power consumption and thinness as one of flat panel displays that replace CRTs. Display elements using liquid crystals include simple matrix liquid crystal display devices and TFT-LCDs using TFTs as switching elements. TFT-LCDs having characteristics superior to CRTs and simple matrix type liquid crystal display devices in terms of portability and display quality have been widely put into practical use in notebook personal computers and the like.

  In a TFT-LCD, a liquid crystal layer is generally sandwiched between a TFT array substrate and a counter substrate. TFTs are formed in a matrix on the TFT array substrate. Polarizers are provided on the outside of the TFT array substrate and the counter substrate, respectively. Furthermore, a backlight is provided on one side. With such a structure, a good color display can be obtained.

  However, in the TFT-LCD, it is necessary to create a TFT array substrate in which TFTs are formed in a matrix on a glass substrate using semiconductor technology, and a large number of processes are required. For this reason, various defects and defects are likely to occur, resulting in a decrease in yield, and there is a problem that the number of devices necessary for manufacturing increases and the manufacturing cost increases.

  As a method for solving such a problem, a manufacturing method of an active matrix liquid crystal display device in which a TFT array substrate is formed by four photolithography processes is performed. In this manufacturing method, when forming a channel portion of a TFT that is a switching element, exposure is performed using a gray-tone mask or a half-tone mask that is a semi-transmissive exposure mask. Thereby, a resist shape as shown in FIG. 6A can be formed. Specifically, the resist shape is such that the thickness of the resist on the channel portion is thinner than the others.

  In a state where such a resist is formed, a portion not covered with the resist is first etched to pattern the electrode layer and the semiconductor layer. Thereafter, the resist film thickness is reduced by a resist ashing process or the like, and the ashing process is stopped in a state in which the resist is removed only in a channel portion thinner than the others. By forming the channel portion, the semiconductor film and the source / drain electrodes can be formed in one exposure process, and the active matrix liquid crystal display device can be manufactured in four exposure processes as a whole.

  Here, the finished film thickness of the resist thinner than the others on the channel part is very important, and it is necessary to strictly manage the finished standard. This is because if the resist film on the channel part is too thick, the resist in the channel part cannot be removed in a predetermined ashing time. For this reason, TFT cannot be formed, resulting in a display defect and a defect. On the other hand, if the film thickness of the resist on the channel portion is too thin, the resist is removed too much in a predetermined ashing time. For this reason, the width of the channel becomes wider than the design value, TFT characteristics as designed cannot be achieved, resulting in display defects.

  Therefore, it is essential that the resist film thickness of the channel portion is substantially constant in ratio to other thick resist film portions and has good in-plane uniformity. For these reasons, the resist film thickness measurement after exposure and development using a gray tone mask or a half tone mask is a very important inspection item.

  Recently, the measurement of the film thickness and refractive index of a thin film has been widely used based on the principle of a two-dimensional reflection photometer. This is non-contact, non-destructive, can measure the film thickness and refractive index of the multilayer film, and is advantageous in terms of inspection speed and reliability because no special preparation or processing is required for the substrate to be measured. It is.

  A configuration of a two-dimensional reflection photometer generally used for measuring a film thickness of a normal resist or the like is shown in FIGS. 1A and 1B of Patent Document 1. FIG. In the two-dimensional reflection photometer having such a configuration, the measurement target region is determined by the field diameter of the objective lens that receives the reflected light from the measurement substrate and the light detection hole in the optical path. The The higher the magnification, the smaller the visual field diameter, the light quantity decreases, and the detection noise increases. For this reason, the visual field diameter has a practical limit of about 4 μm to 20 μmφ.

On the other hand, in the resist film thickness measurement after exposure and development using the gray-tone mask or half-tone mask of the channel part in the manufacturing process of the active matrix type liquid crystal display device formed by four photolithography processes as described above, Measurement of a narrow region of about 0.2 to 0.5 μmφ is required. In response to such a requirement, the substrate to be measured is irradiated with light, the reflected light is switched for each wavelength by a spectral filter and received by a CCD, and the signal is subjected to arithmetic processing, thereby approximately 0.2 to 0. A configuration of a two-dimensional reflection photometer capable of measuring a narrow region of .5 μmφ is shown in FIG.
JP 2005-503547 A

  However, even with such a two-dimensional reflection photometer, there are the following problems. First, in order to specify measurement in a narrow region of about 0.2 to 0.5 μmφ, alignment of measurement points is important. In the method of aligning the registered image and the image of the measurement point with the image recognition technology, the alignment accuracy is 0.5 to 1 μm, and therefore the measurement point is misaligned. Also, there is a function of detecting edges at both ends of the channel portion from the optical density and setting the centers of the detected both ends as the channel center portion. However, as shown in FIG. 6A, since the edges at both ends of the channel portion are gently curved, the detection of the edges is very difficult and often does not function substantially. For this reason, there is a problem in that the set measurement point is shifted and the minute region cannot be measured with high positional accuracy.

  Further, as described above, the resist shown in FIG. 6A is formed by dimming using a gray-tone mask or a half-tone mask which is a semi-transmissive exposure mask. In particular, the gray-tone mask is developed by exposing to light with an appropriate exposure amount of several tenths of light by blurring an optical image by causing interference with a slit pattern less than the optical resolution performance of the exposure apparatus. For this reason, the resist surface is microscopically rough and uneven, and the reflected light is easily scattered. Further, the shape of the resist itself on the channel portion also forms a gentle curved surface as shown in FIG. 6A as described above, and there is a ratio that the directions of reflected light from the upper and lower surfaces of the resist do not coincide with each other. In many cases, there is a problem that the signal intensity obtained by interference is reduced.

  For this reason, in the flat resist shown in FIG. 5A, the interference waveform (measurement waveform) obtained by the measurement and the interference waveform (theoretical waveform) almost coincide as shown in FIG. 5B. On the other hand, in the resist shown in FIG. 6A, as shown in FIG. 6B, the measured waveform is very often compared to the theoretical waveform obtained from the value theory calculation. For this reason, when comparing the measured waveform of incident light and reflected light with the theoretical waveform obtained from theoretical calculation using the nonlinear error minimization method, it is not possible to measure, or other film thickness values are incorrectly determined. Was produced.

  FIG. 7 shows a conventional determination method for the measurement result. As shown in FIG. 7, in the conventional determination method, a measured waveform and a theoretical waveform are compared with respect to a plurality of measurement points designated in the same field of view, and a root mean square error (RMSE) is calculated. Each film thickness is calculated by iterative calculation by the minimization method (S1). If the change rate of the RMSE value does not fall within the specified convergence value within the specified number of times (S2), it is displayed as a measurement error (S3). If the converged RMSE value is not within the specified value (S4), it is similarly displayed as a measurement error (S3).

  Thereafter, when the calculation of the film thickness of all the points designated in the same field of view is completed (S5), it is determined whether there are other measurement points with different measurement positions on the substrate (S6), and all the measurement points are determined. The above processing is performed. Then, the measurement result of the measurement point that caused the measurement error is deleted from the statistical data for performing statistical processing such as maximum, minimum, average, uniformity, standard deviation, etc., and the change rate of the RMSE value is within the convergence specified value. Data statistical processing is performed using the measurement results of the measurement points (S7). However, the conventional method does not deal with the situation as described above, and the reliability of the measurement result is insufficient.

  The present invention has been made in order to solve such problems, and the object of the present invention is to provide a case where the surface of the thin film is wavy in a minute region or where there is a minute surface roughness. An object of the present invention is to provide a film thickness measuring apparatus and a film thickness measuring method capable of improving the reliability of measurement.

  A film thickness measuring apparatus according to an aspect of the present invention is a film thickness measuring apparatus that measures the film thickness of a thin film provided on a substrate to be measured, the optical system irradiating light to the substrate to be measured, and the target A spectroscopic unit that splits the reflected light from the measurement substrate, a light detection unit that detects the light split by the spectroscopic unit, and outputs a signal according to the intensity of the detected light, and is output by the photodetection unit. An information processing unit that calculates the film thickness of the thin film based on an error between the signal and the theoretical waveform, and the information processing unit includes a grouping unit that groups measurement points, and a plurality of groups grouped as the same group. In the measurement data of the measurement point, determination means for determining a part as a measurement error according to at least one of the film thickness and the error of the thin film, and statistical processing of the measurement data determined as the measurement error The Except from Utame statistical data, and includes a statistical processing unit configured to perform statistical processing.

  A film thickness measuring method according to an aspect of the present invention is a film thickness measuring method for measuring a film thickness of a thin film provided on a substrate to be measured, the step of irradiating the substrate to be measured with light, and the device to be measured Based on an error between the step of splitting the reflected light from the substrate, the step of detecting the split light and outputting a signal according to the intensity of the detected light, and the output signal and the theoretical waveform, The step of calculating the film thickness of the thin film, grouping the measurement points, and measuring data according to at least one of the film thickness of the thin film and the error in the measurement data of a plurality of measurement points grouped as the same group. And a step of performing statistical processing by removing the measurement data determined as the measurement error from the statistical data for performing statistical processing.

  According to the present invention, a film thickness measuring apparatus and a film thickness measurement capable of improving the reliability of measurement even when there is a portion where the surface of the thin film is wavy in a minute region or a portion where there is fine surface roughness. A method can be provided.

  Embodiments to which the present invention can be applied will be described below. The following description is to describe the embodiment of the present invention, and the present invention is not limited to the following embodiment. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate.

  In a manufacturing method of an active matrix type liquid crystal display device in which a TFT array substrate is formed by four photolithography processes, exposure and development are performed using a gray-tone mask or a half-tone mask which is a semi-transmissive exposure mask on a TFT channel portion or the like. In this case, a resist including a portion where the surface of the thin film is wavy in a minute region or a portion where there is a minute surface roughness is formed on the substrate. When the film thickness of the resist is measured, the signal intensity obtained by the interference decreases, and the interference waveform obtained as a result of the measurement becomes a waveform that is broken compared with the theoretical waveform obtained from the theoretical calculation. For this reason, the measurement waveform of a certain film thickness range is similar to the theoretical waveform of another film thickness. When the film thickness is calculated by the nonlinear error minimization method, The present inventor has found that the error is smaller and gives erroneous measurement results.

  In the present invention, a function for grouping measurement points and a part of measurement data of a plurality of measurement points grouped as the same group according to at least one of the thickness of the thin film and the error as a measurement error. Added a process to determine and remove the measurement data determined as a measurement error from the statistical data for statistical processing. Hereinafter, embodiments of the present invention will be described in detail.

Embodiment 1 FIG.
A film thickness measuring apparatus according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a configuration of a film thickness measuring apparatus 10 according to the present embodiment. As shown in FIG. 1, the film thickness measuring apparatus 10 includes a stage 11, a light source lamp 12, a semi-transmissive mirror 13, an objective lens 14, an optical system 15, a spectrometer 16, a photodetector 17, and an information processor 20. Yes. On the stage 11, a substrate to be measured W that is a measurement target is placed. Here, it is assumed that the substrate to be measured W is composed of a substrate S and a resist L formed thereon as shown in FIG. As shown in FIG. 6A, the substrate to be measured W has such a shape that the thickness of the resist on the region that becomes the channel portion of the TFT is thinner than the others.

  The light source lamp 12 emits illumination light that irradiates the substrate W to be measured. Illumination light from the light source lamp 12 enters the semi-transmissive mirror 13 and is reflected toward the objective lens 14. Then, the light is condensed on the measurement target substrate W through the objective lens 14. A part of the light irradiated to the substrate to be measured W is reflected on the surface of the resist L, that is, the interface between the resist L and the atmosphere. A part of the light passes through the resist L and is reflected at the surface of the substrate S, that is, at the interface between the substrate S and the resist L.

  The light reflected by the substrate to be measured W passes through the objective lens 14 again and enters the semi-transmissive mirror 13. Then, the light transmitted through the semi-transmissive mirror 13 is irradiated to the spectroscope 16 through the optical system 15. The spectroscope 16 splits the incident reflected light and outputs it to the photodetector 17. Note that the spectroscope 16 can selectively narrow-band filter the wavelength of the light and repeat this multiple times to split the incident reflected light. By obtaining a plurality of pieces of light intensity information obtained by the narrow band filter, spectral information over a wide band can be obtained.

  From the result obtained by the photodetector 17 after passing through the spectroscope 16, the film thickness of the resist L is obtained through the information processor 20. Specifically, the intensity of the reflected light with respect to various wavelengths obtained by the spectroscope 16 is converted into numerical measurement data by the photodetector 17. The photodetector 17 is, for example, a CCD (Charge Coupled Device) or an image sensor. Then, the film thickness is measured by performing the processing described below with the information processor 20.

  Here, the configuration of the information processor 20 will be described in more detail with reference to FIG. The information processor 20 includes a film thickness calculation unit 21, a grouping unit 22, a setting unit 23, a determination unit 24, a statistical processing unit 25, and the like. The film thickness calculation means 21 calculates the film thickness of the resist L based on the measurement data of each wavelength converted by the photodetector 17. Specifically, the film thickness calculation means 21 compares the measured interference waveform (measurement waveform) with the interference waveform (theoretical waveform) calculated by theoretical calculation, and calculates the root mean square error (RMSE). The film thickness is calculated by iterative calculation using the minimization method.

  The grouping unit 22 groups measurement points. For example, in the present embodiment, a plurality of measurement points in a thin part with the same film thickness of the resist L by design are grouped into one group, and a plurality of measurement points in a thick part with the same film thickness by design are similarly set as another group. Can be a group of.

  The setting means 23 sets the target numerical value range setting value (setting value 1) and the variation range allowable setting value (setting value 2) in order to eliminate measurement errors. As the target numerical value range setting value (setting value 1), a numerical value range in which a measurement error is likely to occur is set. For example, the measurement waveform when the film thickness of the resist L is 2700 mm to 3200 mm approximates the theoretical waveform when the thickness of the resist L is 1200 mm to 1500 mm. Therefore, when the film thickness is determined by the RMSE value minimization method, the film thickness of the resist L is actually erroneously determined to be 1200 mm to 1500 mm even though it is in the range of 2700 mm to 3200 mm. There is. In the present invention, a set value is provided to eliminate this.

  Here, it is assumed that the film thickness of the resist L is in the range of 2700 mm to 3200 mm. In this case, the set value 1 can be set to, for example, 1200 mm to 1500 mm. The measurement data outside the range of the set value 1 is determined to be positive data because the true film thickness is rarely erroneously determined. On the other hand, since the measurement data within the range of the set value 1 often erroneously determines that the true film thickness is a different film thickness, the measurement data is used as the determination target data, and the following set value 2 It is determined whether or not there is erroneous data by comparison with.

  The variation range allowable set value (set value 2) is set in consideration of a normal variation range when no measurement error occurs. The difference between the data to be determined included in the set value 1 and the maximum of the measurement data outside the range of the set value 1 is calculated, and it is determined whether this is within the set value 2. If these differences are within the set value 2, the measurement data is determined to be positive data. On the other hand, if these differences are larger than the set value 2, the data is determined to be erroneous data.

  For example, as described above, when the setting value 1 is set to 1200 mm to 1500 mm, and the measurement data is 1300 mm, the measurement data is determined data. When the maximum data outside the range of the setting value 1 is 3200 mm, the difference between these is 3200-1300 = 1900 mm. When the set value 2 is set to 1200 mm, the difference between the maximum measured data outside the range of the set value 1 and the determination target data is larger than the set value 2 or more. For this reason, it is determined that the measurement data is erroneous data. Note that these setting values 1 and 2 are examples, and can be changed as appropriate.

  The statistical processing means 25 deletes the data determined as erroneous data by the above setting values 1 and 2 among the plurality of measurement data at the measurement points set as the same group. The statistical processing means 25 performs statistical processing such as maximum, minimum, average, uniformity, standard deviation, etc., using the measurement data determined as positive data.

  Here, with reference to FIG. 3, the film thickness measuring method in the film thickness measuring apparatus 10 shown in FIG. 1 will be described. FIG. 3 is a flowchart for explaining the film thickness measuring method according to the present embodiment. Measurement points are grouped in advance by the grouping means 22. For example, a plurality of measurement points in a thin portion where the resist L is designed to have the same film thickness are set as the same group.

  Then, as shown in FIG. 3, first, a measured waveform measured at a plurality of measurement points designated within the same field of view is compared with a theoretical waveform calculated by theoretical calculation, and the root mean square error is minimized. Each film thickness is calculated by iteratively calculating (S10). Then, it is determined whether or not the RMSE value is within a specified convergence value (S11). In the case of determining the film thickness by performing curve fitting by the non-linear least square method, the RMSE value is calculated in comparison with the theoretical waveform of each film thickness, and preferably the value that minimizes the RMSE value is determined as the film thickness.

  However, since it takes time to calculate the minimum value of the RMSE value, a convergence designated value of the RMSE value is set here. The convergence specification value is a threshold value used when determining the film thickness, and a change rate of a predetermined RMSE value is set. If the RMSE value is equal to or less than the convergence specified value, the film thickness corresponding to the fitted theoretical waveform can be set as the film thickness at the measurement point.

  If the rate of change of the RMSE value is not within the specified convergence value (S11, No), the process returns to S1 and is compared again with the theoretical waveform corresponding to a different film thickness to calculate the RMSE value. When the change rate of the RMSE value does not fall within the specified convergence value within the specified number of times, the measurement result at the measurement point is displayed as a measurement error (S19). When the change rate of the RMSE value is within the specified convergence value (S11, YES), if the converged RMSE value is not within the specified value (S12, NO), it is similarly displayed as a measurement error (S19). The measurement result of the measurement point that caused the measurement error is deleted from the statistical data for performing statistical processing such as maximum, minimum, average, uniformity, standard deviation.

  Thereafter, it is determined whether or not the calculation of the film thickness at all the points designated in the field of view has been completed (S13). If the calculation has not been completed, the film thickness at that point is similarly calculated. If the film thicknesses of all points have been calculated, it is determined whether or not the data is group-set data (S14). If the data is not group-set data, the process jumps to S17. For group-set data, the following processing is performed.

  Thereafter, it is determined whether the measurement data in the group is within the range of the set value 1 (S15). As described above, the set value 1 is set to a numerical range in which measurement errors are likely to occur. If the measurement data in the group is outside the range of the set value 1 (S15, No), the possibility of a measurement error is low, and the measurement data is used as positive data for subsequent statistical processing. On the other hand, when the measurement data is included in the range of the set value 1 (S15, YES), since the measurement error is likely to occur, the data is determined data.

  Thereafter, it is determined whether or not the difference between the data to be determined that is measurement data within the range of the set value 1 and the most different maximum value of the measurement data determined as positive data is equal to or less than the set value 2 (S16). . In S16, if the difference between the judged data and the maximum value of the measurement data is equal to or less than the set value 2 (YES), the data is determined as positive data. On the other hand, if the difference between the data to be judged and the maximum value of the measurement data is larger than the set value 2 (NO), it is judged as erroneous data and displayed as a measurement error (S20). The measurement data at the measurement point that caused the measurement error is deleted from the statistical data for performing statistical processing such as maximum, minimum, average value, uniformity, and standard deviation. Thereafter, it is determined whether or not other measurement points remain (S17), and the above processing is performed for all measurement points. Then, data statistical processing is performed using data determined as positive data in S15 and S16 (S18).

  As described above, in the present invention, the function for grouping measurement points, the target numerical value range setting value (setting value 1), and the variation range allowable setting value (setting value 2) are set and set as the same group. In addition, a function for comparing a plurality of measurement data with the set values 1 and 2 to determine an error is provided. And the determination process which removes the measurement data made into the measurement error from the statistical data for performing a statistical process was added. For this reason, compared to film thickness measurement, which has been performed repeatedly using the conventional nonlinear error minimization method, erroneous measurement can be eliminated, and the reliability of the measurement results is improved. Can be prevented and the product quality is improved.

Embodiment 2. FIG.
A film thickness measurement method according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 4 is a flowchart for explaining the film thickness measuring method according to the present embodiment. Note that the schematic configuration of the film thickness measurement apparatus is the same as that described in Embodiment 1, and thus the description thereof is omitted.

  In the manufacturing process of the active matrix type liquid crystal display device in which the TFT array substrate is formed by four photolithography processes, as shown in FIG. 6A, the resist L formed on the substrate S is the channel portion of the TFT. Thus, the resist film thickness on the region becomes a shape that is thinner than the others. When measuring the resist film thickness on this channel part, the interference waveform is the most uniform in the center part of the channel, the convergence value of the nonlinear error becomes the smallest, and the convergence value of the nonlinear error becomes larger toward both ends of the channel. The present inventors have found that.

  In this embodiment, in order to measure the center portion of the channel with high positional accuracy, measurement points are set continuously across the channel portion to be measured, and these measurement points are grouped. At this time, in consideration of the alignment accuracy of the film thickness meter in addition to the channel width, the measurement points are arranged wider than the channel width. This is so that the center portion of the channel enters somewhere in the row of measurement points even if misalignment occurs.

  As shown in FIG. 4, first, a measured waveform measured at a plurality of measurement points designated within the same field of view is compared with a theoretical waveform calculated by theoretical calculation, and iteratively performed by a method of minimizing the root mean square error. To calculate each film thickness (S21). Then, it is determined whether or not the change rate of the RMSE value is within the convergence specified value (S22). When the change rate of the RMSE value is not within the convergence specified value (S22, No), the process returns to S21 and is compared again with the theoretical waveform corresponding to a different film thickness to calculate the RMSE value. When the change rate of the RMSE value does not fall within the specified convergence value within the specified number of times, the measurement result at the measurement point is displayed as a measurement error (S29).

  When the change rate of the RMSE value is within the specified convergence value (S22, YES), if the converged RMSE value is not within the specified value (S23, NO), the measurement error is similarly displayed (S29). The measurement result of the measurement point that caused the measurement error is deleted from the statistical data for performing statistical processing.

  Thereafter, it is determined whether or not the calculation of the film thickness at all the points designated in the field of view has been completed (S24). If the calculation has not been completed, the film thickness at that point is similarly calculated. If the film thicknesses of all the points have been calculated, it is determined whether or not the data is set in the group (S25). If the data is not set in the group, the process jumps to S27. For group-set data, the following processing is performed.

  Next, it is determined whether or not the convergence value of the nonlinear error at these measurement points is minimum (S26). Measurement data of only the measurement point at which the convergence value of the nonlinear error is minimum is determined as positive data (S26, YES). Measurement data at other measurement points where the convergence value of the nonlinear error is not minimum is determined as erroneous data (S26, NO), a measurement error is displayed, and deleted from the statistical data for performing statistical processing (S30). Thereafter, it is determined whether or not other measurement points remain (S27), and the above processing is performed for all measurement points.

  Usually, a plurality of channel portions are formed in the substrate to be measured W. Accordingly, the resist film thickness corresponding to the plurality of channel portions is calculated in the same manner by repeating S21 to S27. Data statistical processing such as maximum, minimum, average value, uniformity, and standard deviation is performed using the measurement data determined as the positive data (S28).

  As described above, according to the present embodiment, it is possible to measure the channel center more accurately and to measure the reliability of the measurement result, compared with the film thickness measurement that has been repeatedly performed by the conventional nonlinear error minimization method. As a result, the yield can be prevented from being lowered due to erroneous measurement, and the product quality is improved.

  Although the embodiment has been described above, in order to further improve the reliability of the measurement value, before the final statistical processing, a determination at the upper limit value of the convergence value of the nonlinear error is added separately. Also good. Specifically, a determination process is added only for measurement points that are equal to or lower than the upper limit set value of the convergence value of the nonlinear error, and others are displayed as measurement errors and excluded from statistical data. As a result, the reliability of the measurement result is further improved, and as a result, a decrease in yield due to erroneous measurement can be prevented, thereby improving the quality of the product.

It is a figure which shows the structure of the film thickness measuring apparatus which concerns on Embodiment 1. FIG. 2 is a diagram illustrating a configuration of an information processing device used in the film thickness measurement device according to Embodiment 1. FIG. 3 is a flowchart for explaining a film thickness measuring method according to Embodiment 1. FIG. 10 is a flowchart for explaining a film thickness measuring method according to Embodiment 2. FIG. It is a figure which shows the shape and measurement result of the resist which were formed on the board | substrate. It is a figure which shows the shape and measurement result of the resist which were formed on the board | substrate. It is a flowchart for demonstrating the conventional film thickness measuring method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Film thickness measuring apparatus 11 Stage 12 Light source lamp 13 Semi-transmission mirror 14 Objective lens 15 Optical system 16 Spectrometer 17 Photo detector 20 Information processor 21 Film thickness calculation means 22 Grouping means 23 Setting means 24 Determination means 25 Statistical processing means W Substrate to be measured S substrate L resist

Claims (8)

A film thickness measuring device for measuring a film thickness of a thin film having a locally different film thickness provided on a substrate to be measured,
An optical system for irradiating the substrate to be measured with light;
A spectroscopic unit that splits the reflected light from the substrate to be measured;
A light detection unit that detects light split by the spectroscopic unit and outputs a signal corresponding to the intensity of the detected light;
An information processing unit that calculates a film thickness of the thin film based on an error between the signal output by the light detection unit and a theoretical waveform;
The information processing unit
Grouping means for grouping a plurality of measurement points in the same field of view according to the film thickness of the thin film ;
In the measurement data of a plurality of measurement points grouped as the same group, the numerical value range of the film thickness having a theoretical waveform that approximates the signal of the group is set as the target numerical value range, and the variation range allowable setting value is set Setting means;
Among the measurement data of the plurality of measurement points, the difference between the determination data included in the target numerical value range and the measurement data different from the determination data other than the determination data is acceptable for the variation range. A determination means for determining a measurement error that is larger than the set value ;
Statistical processing means for performing statistical processing, excluding the measurement data determined as the measurement error from statistical data for performing statistical processing;
A film thickness measuring device comprising: The film thickness measuring apparatus according to claim 1 , wherein the grouping unit sets measurement points corresponding to regions having substantially the same film thickness as the same group. A film thickness measuring device for measuring a film thickness of a thin film having a locally different film thickness provided on a substrate to be measured,
An optical system for irradiating the substrate to be measured with light;
A spectroscopic unit that splits the reflected light from the substrate to be measured;
A light detection unit that detects light split by the spectroscopic unit and outputs a signal corresponding to the intensity of the detected light;
An information processing unit that calculates a film thickness of the thin film based on an error between the signal output by the light detection unit and a theoretical waveform;
The information processing unit
Grouping means for setting the measurement points arranged in approximately one row from a thick region to a thin region of the thin film as the same group;
A determination means for determining at least a part of the measurement data of a plurality of measurement points of the same group as a measurement error at least a part other than the error convergence value being minimum
Statistical processing means for performing statistical processing, excluding the measurement data determined as the measurement error from statistical data for performing statistical processing;
A film thickness measuring device comprising: An upper limit setting means for setting an upper limit value of the error convergence value of each of the measurement data of the plurality of measurement points,
The determination means, the thickness measuring device according to any one of claims 1 to 3, characterized in that to determine the large measurement data than the upper limit value of the error convergence value as a measurement error. A film thickness measuring method for measuring a film thickness of a thin film having a locally different film thickness provided on a substrate to be measured,
Irradiating the substrate to be measured with light;
Spectroscopically analyzing reflected light from the substrate to be measured;
Detecting the dispersed light and outputting a signal according to the intensity of the detected light;
Calculating the film thickness of the thin film based on an error between the output signal and the theoretical waveform;
Grouping a plurality of measurement points in the same field of view according to the thickness of the thin film ;
In the measurement data of a plurality of measurement points grouped as the same group, the numerical value range of the film thickness having a theoretical waveform that approximates the signal of the group is set as the target numerical value range, and the variation range allowable setting value is set Steps,
Among the measurement data of the plurality of measurement points, the difference between the determination data included in the target numerical value range and the measurement data different from the determination data other than the determination data is acceptable for the variation range. Determining a measurement error that is larger than a set value;
Removing the measurement data determined as the measurement error from the statistical data for performing statistical processing, and performing statistical processing;
A film thickness measuring method including: 6. The film thickness measuring method according to claim 5 , wherein the measurement points corresponding to the regions having substantially the same film thickness are set as the same group. A film thickness measuring method for measuring a film thickness of a thin film having a locally different film thickness provided on a substrate to be measured,
Irradiating the substrate to be measured with light;
Spectroscopically analyzing reflected light from the substrate to be measured;
Detecting the dispersed light and outputting a signal according to the intensity of the detected light;
Calculating the film thickness of the thin film based on an error between the output signal and the theoretical waveform;
Setting measurement points arranged in approximately one row from a thick region to a thin region of the thin film as the same group;
Determining at least a part of the measurement data of a plurality of measurement points in the same group as a measurement error other than the one having the smallest error convergence value ;
The measurement data determined as the measurement error, Except from the statistical data for performing statistical processing, and performing statistical processing,
A film thickness measuring method including: Setting an upper limit value of error convergence value of each of the measurement data of the plurality of measurement points,
The film thickness measurement method according to claim 5, wherein measurement data larger than an upper limit value of the error convergence value is determined as a measurement error.

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