Film thickness measuring device and film thickness measuring method

Abstract

To provide a film thickness measurement device and a film thickness measurement method that can measure a film thickness at high speed.SOLUTION: A film thickness measurement device 1 comprises: a light source 10 (light irradiation unit) that planarly irradiates a sample 100 (object) with light; a tilted dichroic mirror 22 (optical element) that has transmittance and reflectance changing according to a wavelength in a predetermined wavelength region, and transmits and reflects light from the object to separate the light; area sensors 23, 24 (imaging units) that pick up an image of the light separated by the optical element; and a controller 30 (analysis unit) that estimates the film thickness of the object on the basis of signals from the imaging units that pick up the images of light. The light irradiation unit irradiates the object with light with a wavelength included in the predetermined wavelength region of the optical element.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] One aspect of the present invention relates to a film thickness measuring apparatus and a film thickness measuring method.

Background Art

[0002] For example, in semiconductor manufacturing equipment and the like, it is important to form a film uniformly on the wafer surface. When the in-plane uniformity of the film thickness value is poor, failure factors such as wiring defects and voids occur, and the yield deteriorates. In this case, the productivity deteriorates due to an increase in the process time and materials, which becomes a problem. Therefore, in semiconductor manufacturing equipment and the like, usually, the film thickness is measured by a point sensor or a line scan (see, for example, Patent Document 1) or the like, and it is determined whether the desired film thickness distribution is achieved.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, in the method of measuring the film thickness by the above-described point sensor or line scan or the like, the problem is that the measurement time becomes long.

[0005] One aspect of the present invention has been made in view of the above circumstances, and an object thereof is to provide a film thickness measuring apparatus and a film thickness measuring method capable of measuring the film thickness at high speed.

Means for Solving the Problems

[0006] A film thickness measuring device according to one aspect of the present invention comprises a light irradiation unit that irradiates light onto an object in a planar manner, an optical element whose transmittance and reflectance change according to wavelength in a predetermined wavelength range and separates light from the object by transmitting and reflecting it, an imaging unit that images the light separated by the optical element, and an analysis unit that estimates the film thickness of the object based on the signal from the imaging unit that has imaged the light, wherein the light irradiation unit irradiates light with wavelengths included in the predetermined wavelength range of the optical element.

[0007] In a film thickness measuring device according to one aspect of the present invention, light with a wavelength included in a predetermined wavelength range of an optical element is irradiated onto the object in a planar manner. In this film thickness measuring device, the optical element separates the light from the object by transmitting and reflecting it. Here, the transmittance and reflectance of the optical element change depending on the wavelength within the predetermined wavelength range. Therefore, the proportion of light transmitted and the proportion of light reflected in the light separated by the optical element change depending on the wavelength. The separated light is then captured by the imaging unit, making it possible to determine the proportion of transmitted light and the proportion of reflected light, and as a result, the wavelength can be determined. Furthermore, the analysis unit estimates the film thickness of the object based on the signal from the imaging unit. Since the film thickness can be estimated based on information indicating the wavelength, and as described above, the wavelength is determined from the imaging result in the imaging unit, the film thickness of the object can be estimated with high accuracy by considering the signal containing the information of that wavelength (the signal from the imaging unit). Furthermore, in this film thickness measuring device, light is irradiated onto the object in a planar manner, and the film thickness within the object's surface is simultaneously estimated according to the light from the object. Therefore, compared to cases where the film thickness within the surface is estimated while the light irradiation range is changed by a point sensor or line scan, the in-plane film thickness distribution can be estimated at high speed. As described above, according to one aspect of the present invention, the film thickness of an object can be measured at high speed.

[0008] In the above-described film thickness measuring device, the analysis unit may estimate the film thickness corresponding to each pixel based on the wavelength information for each pixel in the imaging unit. With such a configuration, the film thickness distribution on the irradiated surface of the object can be estimated in more detail (for each pixel).

[0009] In the above-described film thickness measuring device, the analysis unit may further consider the angle of light irradiated onto the object when estimating the film thickness. Since the optical path changes when the angle of light irradiated onto the object changes, it may not be possible to estimate the film thickness with high accuracy using only wavelength information. In this regard, by further considering the angle of light irradiated onto the object, the film thickness can be estimated with higher accuracy according to the actual optical path.

[0010] In the above-described film thickness measuring device, the light irradiation unit may irradiate the object with diffused light. This allows for uniform irradiation of the object's surface.

[0011] In the above-described film thickness measuring device, the light irradiation unit may have a light guide plate that generates diffused light. This allows for a compact configuration and uniform irradiation of the surface of the object.

[0012] The above-described film thickness measuring device may further include a bandpass filter positioned between the optical element and the imaging unit. This allows light outside the desired wavelength range to be removed, thereby improving the accuracy of film thickness estimation.

[0013] A method for measuring film thickness according to one aspect of the present invention includes: a first step of irradiating an object with light in a planar manner; a second step of imaging light separated by an optical element whose transmittance and reflectance change according to wavelength in a predetermined wavelength range and which separates the light from the object by transmitting and reflecting it; and a third step of deriving a wavelength based on the imaging result and estimating the film thickness of the object based on the wavelength. With such a film thickness measurement method, the film thickness of an object can be measured at high speed, similar to the film thickness measuring device described above. [Effects of the Invention]

[0014] According to one aspect of the present invention, the film thickness of an object can be measured at high speed. [Brief explanation of the drawing]

[0015] [Figure 1] This is a diagram schematically showing a film thickness measuring apparatus according to an embodiment of the present invention. [Figure 2] This is a diagram schematically showing an example of a light source, where Fig. 2(a) shows flat dome illumination and Fig. 2(b) shows dome illumination. [Figure 3] This is a diagram for explaining the relationship between the characteristics of a dichroic mirror and the wavelength of light emitted from a light source. [Figure 4] This is a diagram for explaining the spectrum of light and the characteristics of an inclined dichroic mirror. [Figure 5] This is a diagram for explaining the wavelength shift according to the transmitted light amount and the reflected light amount. [Figure 6] This is a diagram showing the relationship between wavelength and film thickness. [Figure 7] This is a diagram for explaining the principle of film thickness measurement. [Figure 8] This is a diagram for explaining the difference in the incident angle of light with respect to a camera system. [Figure 9] This is a diagram for explaining the correction of the measured film thickness value. [Figure 10] This is a diagram showing the comparison result between the film thickness measuring apparatus according to this embodiment and a comparative example. [Figure 11] This is a diagram for explaining the film thickness measuring apparatus according to a modified example. [Figure 12] This is a diagram for explaining the film thickness measuring apparatus according to a modified example. [Figure 13] This is a diagram schematically showing the film thickness measuring apparatus according to a modified example.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals, and duplicate explanations are omitted.

[0017] Figure 1 is a schematic diagram of the film thickness measuring device 1 according to this embodiment. The film thickness measuring device 1 is a device that irradiates light onto a sample 100 (object) in a planar manner and measures the thickness of the film formed on the sample 100 based on the reflected light from the sample 100. The sample 100 may be a light-emitting element such as an LED, mini-LED, μLED, SLD element, laser element, vertical-cavity-cell-scale (VCSEL), or an OLED, or it may be a light-emitting element whose emission wavelength is adjusted by a fluorescent material containing nanodots or the like.

[0018] As shown in Figure 1, the film thickness measuring device 1 comprises a light source 10 (light irradiation unit), a camera system 20, and a control device 30 (analysis unit).

[0019] The light source 10 irradiates light onto the sample 100 in a planar manner. For example, the light source 10 irradiates light onto substantially the entire surface of the sample 100 in a planar manner. The light source 10 is, for example, a light source capable of uniformly irradiating the surface of the sample 100, and irradiates the sample 100 with diffused light. As shown in Figure 2, the light source 10 may be a so-called flat dome type light source 10A (see Figure 2(a)) or a dome type light source 10B (see Figure 2(b)). The light source 10A shown in Figure 2(a) has an LED 10c and a light guide plate 10d. The light guide plate 10d generates diffused light in response to the light irradiated from the LED 10c. The diffused light generated by the light guide plate 10d is reflected by the sample 100 and input to the camera system 20. With such a flat dome type light source 10A, reflections can be suppressed while ensuring a sufficient field of view (for example, a field of view of about 300 mm). The light source 10B includes an LED 10e and a dome portion 10f. Light emitted from the LED 10e is directed onto the inner surface of the dome portion 10f, and diffused light from the inner surface of the dome portion 10f is reflected by the sample 100. The reflected light from the sample 100 is input to the camera system 20. The light source 10 may be a surface illumination unit using a white LED, a halogen lamp, or a Xe lamp, etc.

[0020] The light source 10 irradiates the sample 100 with light of a wavelength included in a predetermined wavelength range of the tilted dichroic mirror 22 (details to be described later) of the camera system 20. As will be described in detail later, the tilted dichroic mirror 22 is an optical element that separates light from the sample 100 by transmitting and reflecting it according to its wavelength. The transmittance and reflectance of the tilted dichroic mirror 22 change according to the wavelength in the predetermined wavelength range mentioned above.

[0021] Figure 3 illustrates the relationship between the characteristics of the tilted dichroic mirror 22 and the wavelength of light emitted from the light source 10. In Figure 3, the horizontal axis represents wavelength, and the vertical axis represents the transmittance of the tilted dichroic mirror 22. As shown in the characteristics X4 of the tilted dichroic mirror 22 in Figure 3, in the tilted dichroic mirror 22, the transmittance (and reflectance) of light changes gradually in accordance with the change in wavelength in a predetermined wavelength range X10, while the transmittance (and reflectance) of light remains constant regardless of the change in wavelength in wavelength ranges other than this specific wavelength range. As shown in Figure 3, the light X20 output from the light source 10 includes light with wavelengths included in the predetermined wavelength range X10 described above. That is, the light source 10 outputs light with a broad spectrum that includes the predetermined wavelength range X10. The wavelength range (interference peak wavelength) for measurement is determined by the material of the film formed on the sample 100 and the measurement film thickness range.

[0022] Returning to Figure 1, the camera system 20 is composed of a lens 21, an inclined dichroic mirror 22 (optical element), area sensors 23 and 24 (imaging units), and bandpass filters 25 and 26.

[0023] Lens 21 is a lens that focuses light from the incident sample 100. Lens 21 may be positioned upstream of the inclined dichroic mirror 22, or it may be positioned in the region between the inclined dichroic mirror 22 and the area sensors 23 and 24. Lens 21 may be a finite focus lens or an infinite focus lens. If lens 21 is a finite focus lens, the distance from lens 21 to the area sensors 23 and 24 is set to a predetermined value. If lens 21 is an infinite focus lens, lens 21 is a collimator lens that converts light from the sample 100 into parallel light, and aberration correction is performed so that parallel light is obtained. The light output from lens 21 is incident on the inclined dichroic mirror 22.

[0024] The tilted dichroic mirror 22 is a mirror made using a special optical material, and is an optical element that separates light from sample 100 by transmitting and reflecting it according to its wavelength. The tilted dichroic mirror 22 is configured such that the transmittance and reflectance of light change according to the wavelength in a predetermined wavelength range.

[0025] Figure 4 illustrates the characteristics of the light spectrum and the tilted dichroic mirror 22. In Figure 4, the horizontal axis represents wavelength, and the vertical axis represents spectral intensity (in the case of the light spectrum) and transmittance (in the case of the tilted dichroic mirror 22). As shown in the characteristics X4 of the tilted dichroic mirror 22 in Figure 4, in the tilted dichroic mirror 22, in a predetermined wavelength range (wavelength range λ1 to λ2), the transmittance (and reflectance) of light changes gradually in accordance with the change in wavelength, while in wavelength ranges other than the predetermined wavelength range (i.e., wavelengths lower than λ1 and wavelengths higher than λ2), the transmittance (and reflectance) of light remains constant regardless of the change in wavelength. In other words, in a specific wavelength band (wavelength range λ1 to λ2), the transmittance of light increases monotonically (reflectance decreases monotonically) in accordance with the change in wavelength. Transmittance and reflectance have a negative correlation; when one increases, the other decreases. Therefore, below, the term "transmittance (and reflectance)" may be used instead of simply "transmittance." Note that "the transmittance of light is constant regardless of the change in wavelength" includes not only cases where it is perfectly constant, but also cases where, for example, the change in transmittance for a change of 1 nm in wavelength is 0.1% or less. At wavelengths lower than λ1, the transmittance of light is approximately 0% regardless of the change in wavelength, and at wavelengths higher than λ2, the transmittance of light is approximately 100% regardless of the change in wavelength. Note that "the transmittance of light is approximately 0%" includes transmittances of approximately 0% + 10%, and "the transmittance of light is approximately 100%" includes transmittances of approximately 100% - 10%. In Figure 4, waveform X1 shows the waveform of light output from light source 10. As shown in waveform X1 in Figure 4, the light output from the light source 10 includes light with wavelengths within a predetermined wavelength range (wavelength range λ1 to λ2) of the tilted dichroic mirror 22.

[0026] Area sensors 23 and 24 capture images of light separated by the tilted dichroic mirror 22. Area sensor 23 captures images of light transmitted through the tilted dichroic mirror 22. Area sensor 24 captures images of light reflected from the tilted dichroic mirror 22. The wavelength range to which area sensors 23 and 24 are sensitive corresponds to a predetermined wavelength range in the tilted dichroic mirror 22 where the transmittance (and reflectance) of light changes according to the change in wavelength. Area sensors 23 and 24 are, for example, monochrome sensors or color sensors. The imaging results (images) from area sensors 23 and 24 are output to the control device 30.

[0027] The bandpass filter 25 is positioned between the tilted dichroic mirror 22 and the area sensor 23. The bandpass filter 26 is positioned between the tilted dichroic mirror 22 and the area sensor 24. The bandpass filters 25 and 26 may be filters that remove light in wavelength ranges other than the predetermined wavelength range described above (the wavelength range in the tilted dichroic mirror 22 where the transmittance and reflectance of light change depending on the wavelength).

[0028] Returning to Figure 1, the control device 30 is a computer, and physically comprises memory such as RAM and ROM, a processor (arithmetic circuit) such as a CPU, a communication interface, and storage such as a hard disk. The control device 30 functions by executing programs stored in memory using the CPU of the computer system. The control device 30 may also be composed of a microcontroller or an FPGA.

[0029] The control device 30 estimates the film thickness of the sample 100 based on the signals from the area sensors 23 and 24 that have imaged light. The control device 30 estimates the film thickness corresponding to each pixel based on the wavelength information for each pixel in the area sensors 23 and 24. More specifically, the control device 30 determines the amount of transmitted light specified based on the imaging result (signal from the area sensor 23) in the area sensor 23, the amount of reflected light specified based on the imaging result (signal from the area sensor 24) in the area sensor 24, the center wavelength of the inclined dichroic mirror 22 (the center wavelength of a predetermined wavelength range), and the width of the inclined dichroic mirror 22, and derives the wavelength centroid of light for each pixel, and estimates the film thickness corresponding to each pixel based on the wavelength centroid. The width of the inclined dichroic mirror 22 is, for example, the wavelength width from the wavelength at which the transmittance becomes 0% to the wavelength at which the transmittance becomes 100% in the inclined dichroic mirror 22.

[0030] Specifically, the control device 30 derives the wavelength centroid of each pixel based on the following formula (1). In the following formula (1), λ represents the wavelength centroid, λ0 represents the center wavelength of the inclined dichroic mirror 22, A represents the width of the inclined dichroic mirror 22, R represents the amount of reflected light, and T represents the amount of transmitted light. λ = λ0 + A(T - R) / 2(T + R) (1)

[0031] FIG. 5 is a diagram for explaining the wavelength shift according to the amount of transmitted light and the amount of reflected light. When deriving λ (wavelength centroid) by the above formula (1), as shown in FIG. 5, for pixels where T (amount of transmitted light) = R (amount of reflected light), λ = λ0 (the center wavelength of the inclined dichroic mirror 22). Also, for pixels where T < R, that is, pixels where the amount of reflected light is more than the amount of transmitted light, λ = λ1 (a wavelength on the shorter wavelength side than λ0). Also, for pixels where T > R, that is, pixels where the amount of transmitted light is more than the amount of reflected light, λ = λ2 (a wavelength on the longer wavelength side than λ0). Thus, the value of λ (wavelength centroid) shifts (wavelength shift) based on the amount of transmitted light and the amount of reflected light.

[0032] The method for deriving the wavelength centroid is not limited to the above. For example, since λ (wavelength centroid) is proportional to x as follows, the wavelength centroid may also be derived from equations (2) and (3) below. In equation (3) below, IT represents the transmitted light amount and IR represents the reflected light amount. Furthermore, if the spectral shape of the object to be measured and the line formation of the tilted dichroic mirror 22 are ideal shapes, the parameters a and b in equation (2) can be determined by the optical properties of the tilted dichroic mirror 22. λ = ax + b (2) x = IT - IR / 2(IT + IR) (3)

[0033] In reality, there are differences (individual differences) in the spectral characteristics of the optical system and cameras. Therefore, to compensate for these differences, x may be derived using equation (4) below, for example, by using the signal intensity of a substrate with known reflection characteristics as a reference. In equation (4) below, ITr represents the amount of transmitted light at the reference, and IRr represents the amount of reflected light at the reference. x=(IT / ITr-IR / IRr) / 2(IT / ITr+IR / IRr) (4)

[0034] Alternatively, x may be derived using equation (5) below, using the signal quantity in the non-reflective state in order to eliminate the effect of direct light from the light source. In equation (5) below, ITb represents the transmitted light quantity in the non-reflective state, and IRb represents the reflected light quantity in the non-reflective state. x={(IT-ITb) / (ITr-ITb)-(IR-IRb) / (IRr-IRb)} / 2{(IT-ITb) / (ITr-ITb)+(IR-IRb) / (IRr-IRb)} (5)

[0035] Furthermore, in order to comprehensively implement various corrections such as film characteristics, irradiation spectrum, and nonlinearity of the tilted dichroic mirror 22, the wavelength centroid (λ) may be approximated by a polynomial such as equation (6) below. Note that each parameter (a, b, c, d, e) in equation (6) below can be determined, for example, by measuring multiple samples with different wavelength centroids (film thicknesses). λ = ax⁴ + bx³ + cx² + dx + e (6)

[0036] Figure 6 illustrates the principle of film thickness measurement. In Figure 6, the horizontal axis represents wavelength and the vertical axis represents reflectance. In the examples shown in Figure 6, the relationship between wavelength and reflectance is shown for film thicknesses of 820 nm, 830 nm, and 840 nm. As shown in Figure 6, the wavelength centroid differs depending on the film thickness. Therefore, by identifying the wavelength centroid, it becomes possible to estimate the film thickness.

[0037] The relationship between wavelength and film thickness can be explained by equation (7) below, as shown in Figure 7. In equation (7) below, n is the refractive index of the film, d is the film thickness, m is a positive integer (1, 2, 3, ...), and λ is the wavelength centroid. 2nd represents the optical path difference (the optical path difference caused by the arrangement of the film). Based on equation (7) below, the control device 30 estimates the film thickness corresponding to each pixel from the wavelength centroid of each pixel. 2nd = mλ (m = 1, 2, 3, ...) (Constructive interference condition) 2nd = (m - 1 / 2)λ (m = 1, 2, 3, ...) (Condition for destructive interference) ... (7)

[0038] Here, equation (7), which shows the relationship between wavelength and film thickness as described above, holds true when light is incident perpendicularly to sample 100. On the other hand, equation (7) does not hold true when light is not incident perpendicularly to sample 100. That is, as shown in Figure 8, when light is incident on sample 100 in which a film 101 is placed on the surface of substrate 102, the angle of incidence of the light differs depending on the measurement point, resulting in a different optical path difference. Therefore, it is not possible to estimate the film thickness with high accuracy using equation (7) uniformly. For this reason, in order to estimate the film thickness with high accuracy at any measurement point (angle of incidence), calculations (correction processing) according to the measurement point (angle of incidence) are necessary.

[0039] Figure 9 illustrates the correction of the film thickness measurement. As shown in Figure 9(a), when the angle of incidence of light is θ, the optical path difference is given by 2ndcosθ. Thus, the relationship between wavelength and film thickness considering the angle of incidence θ can be explained by equation (8) below, as shown in Figure 9(b). The control device 30 estimates the film thickness according to the measurement point (angle of incidence) based on equation (8) below. In this way, the control device 30 may further consider the angle of light irradiated onto the sample 100 and estimate the film thickness from the wavelength centroid. 2ndcosθ=mλ (Constructive interference condition) 2ndcosθ=(m-1 / 2)λ (Condition for destructive interference) ··(8)

[0040] As described above, the film thickness measuring device 1 performs a film thickness measuring method. The film thickness measuring method includes, for example, a first step of irradiating the sample 100 with light in a planar manner; a second step of imaging the light separated by an inclined dichroic mirror 22, which separates the light from the sample 100 by transmitting and reflecting light whose transmittance and reflectance change according to the wavelength in a predetermined wavelength range; and a third step of deriving the wavelength based on the imaging result and estimating the film thickness of the sample 100 based on the wavelength.

[0041] Next, the effects and advantages of this embodiment will be described.

[0042] The film thickness measuring device 1 according to this embodiment includes a light source 10 that irradiates light onto a sample 100 in a planar manner, an inclined dichroic mirror 22 whose transmittance and reflectance change according to wavelength in a predetermined wavelength range and separates light from the sample 100 by transmitting and reflecting it, area sensors 23 and 24 that image the light separated by the inclined dichroic mirror 22, and a control device 30 that estimates the film thickness of the sample 100 based on signals from the area sensors 23 and 24 that have imaged the light, wherein the light source 10 irradiates light with wavelengths included in the predetermined wavelength range of the inclined dichroic mirror 22.

[0043] In the film thickness measuring device 1 according to this embodiment, light with wavelengths included in a predetermined wavelength range of the inclined dichroic mirror 22 is irradiated onto the sample 100 in a planar manner. Then, in the film thickness measuring device 1 according to this embodiment, the inclined dichroic mirror 22 separates the light from the sample 100 by transmitting and reflecting it. Here, the transmittance and reflectance of the inclined dichroic mirror 22 change depending on the wavelength in a predetermined wavelength range. Therefore, the proportion of light transmitted and the proportion of light reflected in the light separated by the inclined dichroic mirror 22 change depending on the wavelength. Then, by imaging the separated light with area sensors 23 and 24, the proportion of transmitted light and the proportion of reflected light can be determined, and as a result, the wavelength can be determined. Furthermore, the control device 30 estimates the film thickness of the sample 100 based on the signals from the area sensors 23 and 24. Since the film thickness can be estimated based on information indicating the wavelength, and as described above, the wavelength is determined from the imaging results of the area sensors 23 and 24, the film thickness of sample 100 can be estimated with high accuracy by considering the signal containing the information of that wavelength (the signal from the area sensors 23 and 24). Furthermore, in the film thickness measuring device 1 according to this embodiment, light is irradiated onto the sample 100 in a planar manner, and the film thickness within the plane of the sample 100 is simultaneously estimated according to the light from the sample 100. Therefore, the film thickness distribution within the plane can be estimated at high speed compared to cases where the film thickness within the plane is estimated while the irradiation range of light is changed by a point sensor or line scan, etc. As described above, the film thickness measuring device 1 according to this embodiment can measure the film thickness of sample 100 at high speed.

[0044] Figure 10 shows a comparison between the film thickness measuring device 1 according to this embodiment and a comparative example. As shown in Figure 10, when the film thickness is measured point by point using a point sensor, the measurement time is approximately 4 hours. Here, 4 hours refers to the measurement time when approximately 16,000 points are detected. Also, as shown in Figure 10, when the film thickness is measured line by line scanning, the measurement time is approximately 3 minutes. In contrast, as shown in Figure 10, with the film thickness measuring device 1 according to this embodiment, light is irradiated onto the sample 100 in a planar manner, and the film thickness in the plane is measured all at once (simultaneously), so the measurement time is approximately 5 seconds. Thus, the film thickness measuring device 1 according to this embodiment can estimate the film thickness distribution in a plane at high speed compared to point sensors or line scanning according to the comparative example. Furthermore, with the film thickness measuring device 1 according to this embodiment, the error between the measurement result and the actual film thickness was reduced to 0.1% or less. Thus, the film thickness measuring device 1 according to this embodiment can achieve both a reduction in measurement time and an improvement in measurement accuracy for film thickness. Furthermore, while configurations related to point sensors and line scanning are difficult to integrate in-line (mounted on the device), the film thickness measuring device 1 according to this embodiment can be easily integrated in-line.

[0045] In the above-described film thickness measuring device 1, the control device 30 may estimate the film thickness corresponding to each pixel based on the wavelength information for each pixel in the area sensors 23 and 24. With such a configuration, the film thickness distribution on the irradiated surface of the sample 100 can be estimated in more detail (for each pixel).

[0046] In the above-described film thickness measuring device 1, the control device 30 may estimate the film thickness by further considering the angle of light irradiated onto the sample 100. Since the optical path changes when the angle of light irradiated onto the sample 100 changes, it may not be possible to estimate the film thickness with high accuracy from wavelength information alone. In this respect, by further considering the angle of light irradiated onto the sample 100, the film thickness can be estimated with higher accuracy according to the actual optical path. Specifically, the film thickness is estimated using equation (8) described above.

[0047] In the film thickness measuring device 1 described above, the light source 10 may irradiate the sample 100 with diffused light. This allows the surface of the sample 100 to be irradiated with light uniformly.

[0048] In the film thickness measuring device 1 described above, the light source 10 may have a light guide plate 10d (see Figure 2(a)) that generates diffused light. This allows for a compact configuration and uniform illumination of the surface of the sample 100.

[0049] The above-described film thickness measuring device 1 may further include bandpass filters 25 and 26 positioned between the inclined dichroic mirror 22 and the area sensors 23 and 24. This allows light outside the desired wavelength range to be removed, thereby improving the accuracy of film thickness estimation.

[0050] The film thickness measurement method according to this embodiment is performed by a film thickness measuring device 1 and includes a first step of irradiating a sample 100 with light in a planar manner, a second step of imaging the light separated by an inclined dichroic mirror 22 which separates light from the sample 100 by transmitting and reflecting light whose transmittance and reflectance change according to the wavelength in a predetermined wavelength range, and a third step of deriving the wavelength based on the imaging result and estimating the film thickness of the sample 100 based on the wavelength. With such a film thickness measurement method, the film thickness of the sample 100 can be measured at high speed.

[0051] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. The film thickness measuring device 1 can be applied to measuring the film thickness of various samples 100. As shown in Figure 11, examples of samples 100 include semiconductor elements 100A, flat panel displays 100B, film members 100C, electronic components 100D, and other components other than electronic components 100E.

[0052] In other words, the film thickness measuring device 1 may measure the thickness of the film 101 formed on a substrate 102, which is a wafer, for a semiconductor element 100A. In this case, the device configuration may include a wafer transport and holding mechanism including an arm, cassette, hoop, conveyor, moving stage, etc.

[0053] Furthermore, the film thickness measuring device 1 may measure the thickness of the film 101 formed on a substrate 102 made of glass, film, sheet, etc., for a flat panel display 100B. In this case, the device configuration may include a transport and holding mechanism including an arm, glass stand, conveyor, moving stage, etc.

[0054] Furthermore, the film thickness measuring device 1 may measure the thickness of the film 101 formed on a substrate 102 made of glass, film, sheet, etc., for the film member 100C. In this case, the device configuration may include a transport and holding mechanism including an arm, glass stand, conveyor, moving stage, etc. For the film member 100C, for example, as shown in Figure 12, the film member 100C being transported in one direction may be continuously imaged, and the imaged areas may be joined together to measure the film thickness of the entire transported film member 100C.

[0055] Furthermore, the film thickness measuring device 1 may measure the thickness of the film 101 formed on the substrate 102, which is the substrate, for the electronic component 100D. In this case, the device configuration may include a wafer transport and holding mechanism that includes an arm, cassette, hoop, conveyor, sample stand, moving stage, etc.

[0056] Furthermore, the film thickness measuring device 1 may measure the thickness of the film 101 formed on the substrate 102, which is the base material, for the component 100E. The film on the component 100E is, for example, a thin film such as that of a molded product, and the film thickness measurement in this case refers to, for example, the measurement of the thin film coating thickness. The device configuration may include a wafer transport and holding mechanism that includes an arm, cassette, hoop, conveyor, sample stand, moving stage, etc.

[0057] Furthermore, while the relative film thickness distribution can be derived by the film thickness measurement described above, in addition to this, by detecting spectral information (reference spectral information) from a single point in the sample 100, the absolute values ​​of the film thickness in each area may be derived based on the relative film thickness distribution and the reference spectral information. Figure 13 is a schematic diagram of a modified film thickness measuring device 1A. The film thickness measuring device 1A includes, in addition to the components of the film thickness measuring device 1 described in the embodiment, a half mirror 29 and a spectrometer 50. The half mirror 29 reflects light from, for example, a single point near the center of the sample 100. The spectrometer 50 acquires reference spectral information, which is the spectral data of the light from that single point. By acquiring the reference spectral information in this way, the value of m in equations (7) and (8) can be determined, and not only the relative change in film thickness but also the absolute values ​​of the film thickness in each area can be derived. Note that the method for measuring the absolute value of film thickness is not limited to the above. [Explanation of Symbols]

[0058] 1,1A...Film thickness measuring device, 10...Light source (light irradiation unit), 10d...Light guide plate, 22...Inclined dichroic mirror, 23,24...Area sensor (imaging unit), 25,26...Bandpass filter, 30...Control device (analysis unit), 100...Sample (object).

Claims

1. A light irradiation unit that irradiates light onto an object in a planar manner, An optical element whose transmittance and reflectance change according to wavelength in a predetermined wavelength range, and which separates light from the object by transmitting and reflecting it, A bandpass filter that removes light in wavelength ranges other than the predetermined wavelength range, An imaging unit having an area sensor with multiple pixels, separated by the optical element, and capturing light from the bandpass filter, The system comprises an analysis unit that estimates the film thickness of the object based on the signal from the imaging unit that captures light, The analysis unit is a film thickness measuring device that estimates the film thickness at each pixel based on wavelength information corresponding to each pixel in the plurality of pixels.

2. The film thickness measuring device according to claim 1, wherein the optical element has a transmittance of 0% or 100% in wavelength ranges other than the predetermined wavelength range.

3. The film thickness measuring device according to claim 1, wherein the wavelength information is the wavelength centroid of the light from the object.

4. The film thickness measuring apparatus according to any one of claims 1 to 3, wherein the analysis unit further considers the angle of light irradiated onto the object to estimate the film thickness.

5. In a semiconductor film thickness measuring device for measuring the thickness of a film formed on a wafer substrate, A film thickness measuring device according to any one of claims 1 to 4, The device comprises a transport and holding mechanism for transporting and holding the wafer, which is the object to be transported, The aforementioned film thickness measuring device is a semiconductor film thickness measuring device that determines the thickness of a film formed on the wafer held by the transport and holding mechanism.

6. In a display film thickness measuring device for measuring the thickness of a film formed on a display substrate, A film thickness measuring device according to any one of claims 1 to 4, The system includes a transport and holding mechanism for transporting the aforementioned object, which is a display. The aforementioned film thickness measuring device is a display film thickness measuring device that determines the thickness of a film formed on the display held by the transport and holding mechanism.

7. In a film thickness measuring device for measuring the thickness of a film formed on a substrate of a film member, A film thickness measuring device according to any one of claims 1 to 4, The system includes a transport mechanism for transporting the aforementioned film member, The aforementioned film thickness measuring device is a film thickness measuring device that determines the thickness of the film formed on the film member that has been transported by the transport mechanism.

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