TW200809180A - Method and apparatus for accurate calibration of a reflectometer by using a relative reflectance measurement - Google Patents

Abstract

A reflectometer calibration technique is provided that may include the use of two calibration samples in the calibration process. Further, the technique allows for calibration even in the presence of variations between the actual and assumed properties of at least one or more of the calibration samples. In addition, the technique utilizes a ratio of the measurements from the first and second calibration samples to determine the actual properties of at least one of the calibration samples. The ratio may be a ratio of the intensity reflected from the first and second calibration samples. The samples may exhibit relatively different reflective properties at the desired wavelengths. In such a technique the reflectance data of each sample may then be considered relatively decoupled from the other and actual properties of one or more of the calibration samples may be calculated. The determined actual properties may then be utilized to assist calibration of the reflectometer.

Description

200809180 IX. Description of the invention: [Technical field to which the invention pertains] The present invention relates to the field of optical metrology. More specifically, the present invention provides a method by which the reflectance data can be accurately calibrated. In one embodiment, the present invention provides a method by which a wide frequency vacuum ultraviolet (νυν) reflectance data can be accurately calibrated. Additionally, the present invention also provides a method by which highly accurate film measurements can be performed. [Prior Art] Optical reflection measurement techniques have long been used in process control applications in the semiconductor manufacturing industry due to their non-contact, non-destructive and generally high throughput properties. Most of these tools operate in a portion of the spectral region that spans the deep ultraviolet and near infrared wavelengths (DUV-NIR is typically 2〇〇_1000 nm). The approach to thinner layers and the introduction of complex new materials have challenged the sensitivity of such instruments. As a result, this has forced efforts to develop optical reflectance measuring instruments using shorter wavelengths (below 200 nm), in which greater sensitivity to small changes in material properties can be achieved. A method of performing such measurements is described in U.S. Patent Application Serial No. 10/668,642, filed on Sep. 23, 2003. The content is incorporated herein by reference. In order to obtain meaningful quantitative results from the reflectance measurements, it is necessary to normalize or calibrate the measured reflectance values to produce an absolute reflectance spectrum. At longer wavelengths in the DUV-NIR region, various techniques have traditionally been accomplished using various techniques. Due to the complexity of the absolute reflectometer system, commercial reflectometers are typically measured 120526.doc 200809180 The intensity of the reflection is calibrated according to known absolute reflectance standards. In the DUV-progenitor wavelength range, since the characteristics of the filaments are well known and the reflectance is relatively stable, twinning (which has a native SiO 2 layer) is usually utilized. 3 For different instruments, the precision calibration steps are different, but in essence, the quantity usually measured is '$一Z Equation 1 where Ir is the intensity reflected from the sample and measured by the detector, and “is the incident intensity Ϊ. Usually unknown. In addition, it will change with time due to the environment 2, the optical system offset caused by the change of the environment and the intensity of the light source. At any given time, the calibration procedure determines J. = I cal Ical is the measured intensity of the calibration standard in Equation 2 f, and R... is the assumed reflectivity of the calibration standard. If sufficient information about the calibration sample is known, for example, optical properties, surface roughness, etc. R can be generated using a standard film model: Use this IQ to perform, calibrate the subsequent (4) via Equation! Ca, in practice, this procedure assumes that the change in U is only due to the above. 2 or the lamp intensity changes 'and not because of the calibration standard itself The use of the above methods is generally not detectable with the calibration standard over time, because these changes are simply, calibrated &quot;. Obviously, follow-up The accuracy of the luminosity measurement is stable and stable to the accuracy of the assumption that R- is generated by M and the calibration of the sample itself. 120526.doc 200809180 Qualitative. - The quasi-technical technique involves the complex optical configuration of a moving mirror. </ RTI> </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; The method provides a method of obtaining calibrated reflectance data, but the fact that it is time consuming and involves a lot of mechanical motion and cannot: ★ is easily integrated into a system suitable for use in a semiconductor manufacturing environment. Many of these methods are designed for use in a single wavelength reflectometer, where a wavelength selective pre-monochromator utilizes a single wavelength detector. It is desirable to provide a technique that is both fast and simple at the same time. The broadband reflectance measurement data is calibrated in such a manner as to be suitable for use in a semiconductor manufacturing environment. U.S. Patent No. RE 34,783 proposes a calibration method Therein is described a method comprising: self-absolute reflectance from a well-known calibration sample amount, measuring reflectance, dividing the measured value by an absolute value to obtain a system efficiency coefficient, and then, without changing the illumination or optics The reflectance of the unknown material is measured and applied to the measured value to obtain its absolute value. In practice, single crystal germanium wafers are often used as calibration samples because they are readily available, controllable in manufacturing, and The optical properties in the DUV-NIR region have been well characterized. This method works fairly well at wavelengths above ~250 nm. 'The reflectivity of single crystal germanium at this wavelength is both stable and predictable. At shorter wavelengths (&lt At 250 nm), the reflectivity of single crystal germanium wafers is both unstable and unpredictable. The natural (or "native" formation of the wafer exists on the wafer. 120526.doc 200809180 A small change in the thickness of the emulsified layer can significantly affect the measured reflectance. In addition, it is known that an ultra-thin moisture layer or a smoke layer (in the literature, a Japanese temple called *floating molecular contaminant or just) will be adsorbed onto the surface, and the sample reflectance in this spectral region is further modified. Due to the repeated use in the metrology tool, the 'contaminant film' can also be generated on the calibration sample. The presence and growth of these films can alter the reflectivity of the calibration standard. As a result, it is generally unreasonable to regard the reflectance of a single crystal wafer at a wavelength of &lt;25 〇 nm as &quot;known&quot; characteristics. A method for overcoming this problem is proposed in Japanese Patent No. 5,798,837. The stomach patent describes an optical measurement system comprising a two-reference ellipsometer and at least one non-contact optical measuring device, such as Reflectometer. A reference ellipsometer is used to determine the optical properties of the calibration sample. The optical metrology device is then calibrated by comparing the measured optical characteristics from the optical metrology device to the determined optical properties from the reference ellipsometer. Integrating a separate reference ellipsometer into an optical metrology system is a complex and expensive device. In addition, if the reference ellipsometer is to produce accurate results, it must be properly aligned and calibrated to expand the circular polarimeter itself. Thereafter, it would be highly desirable to develop a method that quickly and accurately calibrates broadband data from an optical reflectometer operating at a wavelength of &lt;250 nm without being associated with incorporating the second reference instrument into the system. Complexity and cost. In addition, it would be advantageous if this method specifically made it possible to accurately calibrate the reflectance data at the skin length including the VUV spectral region, wherein the characteristics of the two-party test standard of the 120526.doc 200809180 are poor. If the small uncertainty of ... can lead to considerable mis-production, this method can be independent of the entire #^ / indeed (the characteristics of this 4 standard in order to reduce or finish 4 (4) and maintenance needs, it will be more ideal Γϊ :: A film that makes accurate calibration of the reflectometry tool possible. A technique is required to perform highly accurate measurements: using optical reflections in a wide range of film applications. Rate, hang using mathematical models to record and then analyze the absolute reflectivity of the sample to determine the type of physical properties. ^ ^Tianjili indicators (usually called, fitness, parameters) to achieve a specific W Unfortunately, the use of the "fitness" parameter is limited, and the accuracy of the measurement is limited. Therefore, afterwards, # need to develop a more sensitive fitness" measurement to obtain a better measurement in the film measurement. High Accuracy, etc. [Invention] The present invention provides a method by which vuv reflectance data can be quickly and materially calibrated. In an embodiment, the method allows the same day to cover a wide range. range Long reflectance data is possible. In addition, the technology operates in a manner that is well suited for use in semiconductor manufacturing environments. The method can be independent because it may not require the use of a second reference. It provides a method. The calibration results can be automatically verified by the method such that the utilization of third party verification criteria will be reduced and/or eliminated altogether. In one embodiment, the technique includes the use of a standard (, calibration, ) sample, even though the standard sample is A small change in the characteristics of the standard sample does not show a significant change in reflectance at the wavelength of interest, and the sample still allows for the registration at the wavelength of 120526.doc 200809180 l. Therefore 'even if it is expected to come across the user Calibration can still be achieved in the case of waves of interest, traditionally significant calibration errors in the zone. ^ This technique can take advantage of the existence of a certain calibration error, which can be referred to as the calibration error function. - The real-medium calibration process may include a technique that uses a first sample and a second sample. The first sample may include a spectral region of interest Significant reflectance changes as a function of sample property change and the second sample may have a relatively uncharacteristic reflectance spectrum in the same-spectral region. The first sample = as a standard or calibration sample, and the second sample may be considered as a reference sample In an embodiment, the spectral region may comprise a νυν spectral region. In another embodiment, a calibration technique is provided, wherein the standard or calibration sample may have relatively unknown characteristics, with the exception that: There is a significant calibration error function in the spectral region. Because &amp;, if it can be assumed that the standard sample exhibits a sharp change in reflectance due to changes in sample characteristics, the exact characteristics of the known standard samples are not required. A technique is provided by which a very accurate film measurement can be performed. This method provides a more sensitive &quot;fitness&quot; indicator for the mathematical fit algorithm, which presents the noise present in the original data. Less sensitive. The fitting program can be a spectrally driven fit program rather than relying solely on amplitude drivers (which typically incorporate difference calculations). In this embodiment, the measurements can be obtained by using the presence of sharp, narrow spectral features. In an embodiment, the measurements are obtained by a spectrally driven fitting procedure that uses the ratio of the expected reflected light of the measured sample to the actual reflected spectrum of the sample being measured, 120526.doc 11 200809180. Therefore, the techniques provided herein use the ratio of the equivalents rather than based on the difference between the expected and actual values. These techniques are especially useful in spectral regions that contain sharp spectral features (e.g., sharp features that are typically not exhibited in the vuv region of a thin film sample). Accordingly, a data convergence technique is provided that can advantageously utilize the absorption edge effects of the disclosed materials. In this way, sharp spectral characteristics (e.g., spectral characteristics caused by interference or absorption effects) are advantageously used to better determine the minimum value of the data indicative of the actual measurement.

In another embodiment, the data reduction technique can use a two-step approach. In this embodiment, a low resolution step such as an amplitude driven fitting procedure may be used first to provide a "rough" measurement. Next, a step such as a spectrally driven fitting procedure can be used to advantageously use the high resolution step of the "absolute" measurement of the presence of sharp spectral features. In an embodiment, the coarse-resolution step can be used to obtain a coarse measurement by utilizing a difference-based technique (as in the "chi-square" advantage function). The high resolution step can be a spectrally driven step that includes a ratio-based technique in the region of interest initially identified by the low resolution technique. In another embodiment, a spectrometer calibration technique is provided. Technique 1 involves the use of two calibration samples during the calibration process. In addition, even if there is a test between the tributary characteristics of the 眚μ and the hypothetical characteristics of at least one or more of the samples in the school, the technique allows 枋^ ί The ratio of the measurement of the first calibration sample to the measurement of the quasi-sample from the target. The actual characteristics of the reference of at least one of the calibration samples are determined. Next, you can use the actual characteristics determined by £ to assist in calibrating the reflectometer. 120526.doc 200809180 In another example using two calibration samples, the intensity of the sample emission is reflected from the second calibration sample = the ratio from the first calibration can be used to exhibit a relative non-reverse intensity at the desired wavelength. In the sample, then, the inverse micro-spectral characteristics of each sample can be considered. In this technique, the reflectivity data of silver + .. can be used to calculate the actual characteristics of the ^ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ The actual characteristics that have been confirmed are used to assist in calibrating the reflective leaves. In another embodiment, a calibration is provided - a system of reflectance data from the first calibration sample, and a reflectance data obtained from the first calibration sample and a reflection from the second calibration sample. Ten of the calibrated samples and at least four of the four samples (four) cutting characteristics may be different from the hypothetical characteristics of the calibration samples, and wherein the reflection of the first calibration sample and the second calibration sample (four) μ 1 method may further include using - based The ratio of the data obtained from the first calibration sample to the data obtained from the second calibration sample to assist the system. In yet another embodiment, a method of calibrating a reflectometer is disclosed. The method can include providing a first calibration sample and a second calibration sample, wherein the first calibration sample and the second calibration sample have different reflection characteristics. The method further includes collecting a first set of data from the first calibration sample and collecting a second set of data from the second calibration sample. The method also includes determining a characteristic of at least one of the first calibration sample and the second calibration sample using a ratio of at least a portion of the first set of data to at least a portion of the second set of data such that the reflection from the unknown sample can be calibrated Rate information. In another embodiment, a method of calibrating a reflectometer is disclosed, wherein the reflectometer operates at a wavelength of 120526.doc -13.200809180 including at least some wavelengths below the deep ultraviolet (DUV) wavelength. The method can include providing a difference in reflection characteristics between the first calibration sample and the second calibration sample and the second calibration sample. The method further includes collecting a first set of data from the first calibration sample, the first set of data comprising at least some intensity data collected for wavelengths below the DUV wavelength. The method also includes collecting a second set of data from the second calibration sample, the second set of data comprising the data of the intensity collected for wavelengths below the DUV wavelength. Additionally 'the method can include using - determining a reflectance of at least one of the first calibration sample and the second calibration sample based on a ratio of the first set of data to the second set of data to be at a wavelength comprising at least some of the duv wavelengths Auxiliary calibration of the reflectometer. In addition - implementation of the combined! In the middle, a method of analyzing the reflectometer data is shown. The method can include providing a first reflectometer sample and at least a second reflectometer: wherein the optical response characteristics of the first calibration sample and the optical response characteristics of the second calibration sample are different. The method further includes collecting the first set of optical response data from the first-reflecting meter sample and collecting the second = optical response data from the second reflectometer sample. The method further comprises using the first set of optical responses to the second set of optical response data in a manner independent of the intensity of the incident reflectometer used in collecting the first set of optical response data and the second set of optical response data At least one characteristic of at least one of the first-reflector sample and the second reflectometer sample is determined. A further understanding of the nature of the advantages of the present invention can be realized after a review of the following description and the accompanying drawings. [Embodiment] The manner in which the standard sample is used to calibrate the 120526.doc -14-200809180 reflectometer is generally proposed in the flowchart of Fig. 1 . As is apparent in the figure, the first step in the calibration process, ^104, assumes an understanding of the reflection characteristics of the standard sample. Once you have this information, record the intensity of the light reflected from the sample as a function of wavelength and calibrate the reflectometer in steps 1〇6. Subsequently, the reflectivity of the unknown sample can then be completely determined by the device in step 1〇8. A more detailed description of this calibration procedure is outlined in Figure Private Chart 202, which presents the mathematical relationships involved in calculating the absolute reflectance of an unknown sample. Figure 2 illustrates a flow chart 202 of the calibration procedure. In a first step 204, an understanding of the reflection characteristics of the standard samples is assumed. Next, in step 206, Z records the intensity of the quasi-sample. Next, in step 208, the source intensity rim is calculated using knowledge of the assumed reflection characteristics of the standard samples. In step 10, 5 has recorded the intensity of the unknown sample. Next, as shown in step 212, the reflectance of the unknown sample can be calculated. Next, the reflectance of the unknown sample can be expressed according to the procedure of step 214. Checking the final step of the process, the measured reflectance of the unknown sample is proportional to the assumed reflectance of the calibration sample. Therefore, if the reflectivity is assumed to be inaccurate, the consequence is that the measured reflectance will also be inaccurate. Early crystal wafers have long been used as calibrations for reflectometers operating in DUV_NIR. Single crystal germanium wafers have proven to be a sensible choice because they are conventional, controllable in manufacturing and optically well characterized in this spectral region. In practice, the hypothetical reflection characteristics of tantalum wafers are calculated using Fresnel Equati〇n and the assumption of the optical properties and thickness of the native ceria surface layer and the optical properties of the tantalum itself. When used to calibrate the reflectance operation at wavelengths greater than approximately 250 11 melons, the 120526.doc -15- 200809180 矽 wafer works well because the underlying assumptions about its physical properties are relatively insensitive to errors in this wavelength region. . In other words, the assumed thickness error of the native oxide layer on the wafer surface does not significantly affect the expected reflectivity of the sample and therefore does not negatively impact the accuracy of the calibration process. This is further illustrated in Figure 3, which presents a calculated reflectance spectrum of a series of Si〇2/Si samples having a thickness of Si〇2 varying from 丨〇 to 3〇A. For example, reflection spectrum 302 illustrates a Si sample having a SiO 2 layer of 1 A, and reflection spectrum 304 illustrates a Si sample having a SiO 2 layer of 30 A. Although the difference between the spectra above 250 nm is quite small, it becomes very noticeable at shorter wavelengths. Therefore, if the thickness of the native oxide layer is assumed to be 丨〇 A and its cross-section is 20 A ', a considerable calibration error will be introduced at wavelengths below 250 nm. Figure 4 better illustrates the effects of these errors. A series of curves corresponding to the ratio of the reflected light rituals are depicted in this figure. The first spectrum in each pair corresponds to the expected spectrum of the SiOVSi sample from the ''hypothesis'' native oxide thickness (which varies from 1〇A to 3〇A), and the second spectrum in each pair corresponds to For Si〇2/Si samples with a 20" "actual" native oxide thickness. Thus, curve 302 of Figure 4 corresponds to the ratio of the reflectance spectrum of the native oxide thickness of 10 A to the reflectance spectrum of the 20 A native oxide thickness. Similarly, curve 304 of Figure 4 corresponds to the ratio of the reflection spectrum of 15 A assuming native oxide thickness to the reflection spectrum of 2 Å A native oxide thickness. In a similar manner, curves 306, 308, and 310 illustrate the ratio of the assumed native oxide thickness of 20, 25, and 30 A to the reflectance spectrum of the native oxide thickness of 20 Å, respectively. In this sense, the ratio is essentially considered as a measure of the calibration error, referred to herein as 120526.doc • 16-200809180 Calibration of the Difference Function (CEF). The closer the CEF is to one, the lower the error associated with the calibration. As shown by curve 306, in the case of "assumed, thickness equal to 2 〇 a" actual, thickness, CEF is equal to one at all wavelengths, and the calibration is completely accurate. In the case of a false thickness of 25 A (only 5 A error), the CEF achieves a value greater than 1.3 at short wavelengths and a value less than 1.002 at wavelengths above 250 nm. This means that the error is greater than 3〇% in VUV and less than ~0.2% at longer wavelengths. Therefore, while germanium wafers are easily used to calibrate reflectometers at wavelengths greater than 25 Å, they do not provide a practical way to accurately calibrate reflectometers in vuvs. In addition, it is generally known that a native Si 2 /Si system will produce an ultra-thin (~i nm or smaller) organic hydrocarbon layer in a normal manufacturing or laboratory environment. Additionally, organic materials can accumulate on the surface of the film during operation of the νυν tool. This type of contaminant layer can be removed by washing this type of contaminant layer in acid or even using the νυν source itself. However, the fluctuating organic layer can significantly fluctuate the reflection characteristics in the νυν region during tool utilization. Since there is a compound based on Shi Xi I burned in a typical manufacturing environment, another source of error is the accumulation of polyoxo-based contaminants on the surface exposed to ν υ 辐射 radiation. This &quot;baked&quot; layer is more difficult to remove. Over time, this contaminant layer accumulates on the surface of the native SiCVSi standard sample, thereby making the absolute reflectance of the standard sample (especially in the vuv region). This means always assuming a native SiCVSi junction. The calibration procedure that produces Rcai often produces erroneous results in vuv. These and normalizations usually affect each measurement and have a significant impact on the sinfulness of vuv reflectance data. A change in the calibration standard itself is required. 120526.doc -17· 200809180 The method of calibrating the program is changed from the system change and the correction is made when the change occurs. The embodiment provides an alternative method to solve these problems. Fig.: The flow chart of the second section 5°2 provides a comprehensive overview of the steps involved in the process. 'This technique requires the use of two samples, one standard sample and one reference #本. Select the standard sample to make it expected to be in a certain ^ The zone exhibits a significant and spectrally sharp CEF. On the other hand, the reference sample is selected such that it exhibits (4) a characteristic reflection spectrum on the same-spectral region. The first two steps, 5〇4 and 5〇6, are actually the same as the conventional method of Figure 所: the steps described, that is, assuming that the knowledge of the characteristics of the standard sample 'then' is recorded as the light intensity reflected from the sample as The wavelength function is used and used to calibrate the reflectometer. At this point, the calibrated reflectometer is used to measure the reference sample and determine its reflectivity as described in step (10). Once this has been done, the reference sample is evaluated in step 510. The measured reflectance characteristics and CEF are used to determine the "actual" characteristics of the standard sample. After grasping the 'actual' characteristics of the standard sample, the reflectometer can then be accurately recalibrated in step 512, thereby In the second step of the process, the inaccuracy caused by the error associated with the π hypothesis characteristic of the standard sample is removed. As in the step, once the instrument has been recalibrated, the absolute reflectance of the unknown sample can be accurately determined. In one embodiment, the calibration technique depends on the choice of standard samples. As noted above, the standard needs to exhibit significant and spectrally sharp in a spectral region of the reflectometer. CEF spectroscopy. To a large extent, the optical properties of the sample 120526.doc •18-200809180 will specify this capability. In particular, the CEF signal produced by the standard sample is expected to correspond to the material containing the standard sample. The optical absorption edge of many increases. In this spectral region, small changes in sample characteristics can produce significant changes in the reflected signal and thus have a large CEF effect. Thereafter, the reflectometer therefore needs to have sufficient spectral resolution. In order to ensure that the sharp features of the CEF signal are detected and resolved. In a preferred embodiment of the invention designed to calibrate a VUV reflectometer, the standard sample comprises a relatively thick deposit on the germanium substrate (~1 〇〇〇〇 Si〇2 layer. Figure 6 presents a CEF curve for this standard, where the ratio of three pairs of reflectance spectra is plotted for the "hypothetical" Si〇2 thickness of 999 〇, ι〇〇〇〇, and 10010 A. As is apparent from the graph, the spectrum 602 corresponding to the 9990 A hypothesis and the spectrum 604 corresponding to the 10010 A hypothesis exhibit substantial and spectrally sharp CEF characteristics (in the π hypothesis ''thickness equals 1 〇〇〇〇A In the case of ''actual' thickness, CEF is equal to one at all wavelengths. In fact, the data in the figure indicates an error of 10 A (only one thousandth) and will introduce more than 200% in the νυν reflectivity result. Inaccuracy. CEF curve with the 20-person SiVOSi sample presented in Figure 4 (in Figure 4, the CEF value at a wavelength longer than 250 nm shows little error (since even if the thickness is assumed to be different from the actual thickness) The fact that CEF is still all close to one. In contrast, when the false thickness is different from the actual thickness, the CEF value of the SiCoSi sample of loooo A plotted in Figure 6 actually exhibits a measurable error at all wavelengths. It is important to note that the sharpest and most intense feature in CEF occurs again in VUV (which is a direct result of the 8丨〇2 absorption edge in this region). 120526.doc -19- 200809180 Although 10,000 A of Si〇 2/Si sample An exemplary standard is provided for the present invention, but since the sample has a significant CEF# number due to a small error in the ''hypothetical' thickness), those skilled in the art will appreciate that many other samples may also function equally. Generally, , assuming any thickness or error in a hypothetical sample characteristic that produces a significant CEF signal. As defined in the scope of this disclosure, CEF is essentially a standard (or, calibration) sample. The ratio of the reflectance spectrum to the "actual" reflectance spectrum. ^ The assumptions about the standard sample are completely accurate, then the CEF assumes a value of one at all wavelengths. Conversely, if the hypothesis is defective to some extent, then cef will exhibit greater than Or less than a value. The greater the imprecision of the hypothesis, the more the cef value deviates from one. Although the CEF clearly provides a sensitive indicator of the accuracy of the calibration, it is itself unobservable. Therefore, a CEF model is used. Use the reference sample to make the CEF feature obvious, because all measurements performed on the sample after the initial calibration are actually the CEF of the sample being studied, The actual &quot;reflection spectral product, so this is the case. Therefore, if a reference sample with a substantially smooth and characteristic reflection spectrum is measured, and if the CEF is not equal to one, then the reflection spectrum recorded in the self-reference sample is strongly (10) The sharp features will be very obvious. Therefore, even if there is no previous reference to the sample, the actual, the fineness of the reflection characteristics is tolerated (unless the reference sample is relatively uncharacteristic in the spectral region of interest), it is possible to easily Evaluating the characteristics of the CEF, 1 thus measuring the accuracy of the initial hypothesis about the characteristics of the standard samples. Although any sample with a substantially smooth and uncharacteristic reflection spectrum can be used as a reference sample, a particularly good choice can be broadband. VUV surface 120526.doc -20- 200809180: Broadband VUV mirror with #12〇〇 coating manufactured by Acton Research, USA. A typical reflection spectrum for this type of mirror is shown in Figure 7. As is apparent from the figure, this wide-band mirror combines the 鬲 reflectivity in the entire vuv region with the non-uncharacterized spectrum. It can be noted from Figure 7 that the test sample does not exhibit sharp features in the spectral region such as VUV (where the standard sample can exhibit significant CEF). Samples used for reference samples do not need to provide a consistent reflectance spectrum between different samples. For example, a broadband vuv mirror of the same type with the same coating from the same manufacturer can exhibit a difference in absolute reflectance between two mirrors. However, if any σ疋 mirror is provided with a relatively smooth and uncharacteristic reflection spectrum (at least in the spectral range of interest), the mirror can be used as a reference sample. Furthermore, even if a reference sample (such as the mirror described above) exhibits an absolute reflectance change over time, the sample is still suitable as a reference sample. Therefore, the repeatability of the multi-test sample and the change in characteristics over time are not as important as the uncharacteristic nature of the sample in the desired spectral range. Those skilled in the art will recognize that a relatively uncharacterized type of sample in the region of interest of the wVUV is a ruthenium sample having native oxide on the sample. When compared to a sample having a thick oxide such as 1000 A of SiOVSi, these samples are relatively uncharacteristic. Thus, as described herein, in an alternative embodiment, the standard sample can be an 8 丨〇 2/8 丨 sample of 1 00 human and the reference sample can be a Shi Xi sample with a native oxide layer. Accordingly, a technique is provided that includes the use of a standard sample, even though the standard m is not exhibiting significant reflectance changes at the wavelength of interest due to small variations in the characteristics of the standard sample, the standard sample is still allowed at the 120526 .doc -21 - 200809180 Equal wavelength towel for calibration. Even if the righteousness encounters a traditionally significant calibration error in the area of interest to the user, 7 J will complete the school rate. In this regard, the technique can take advantage of the presence of a certain amount of calibration error, which can be referred to as a calibration error function. Therefore, the &amp; quasi-process can include a technique that uses the first sample and the second sample. The first sample may include a significant reflectance change as a function of the sample: the change in the spectral region of interest, and the second sample is in the same:

The spectral region can have a relatively uncharacteristic reflection spectrum. The first sample can be regarded as a standard sample or calibration #, and the second sample can be regarded as a reference sample. By first calibrating (4) with a standard sample and then measuring the reference sample, it can be assumed that any sharp change in reflectance observed from the reference sample is a function of the inaccuracy of the false σ of the calibration sample. After mastering this understanding, the new calibration system follows. In addition, the 'calibration technique can produce a standard sample, which can have relatively well-known characteristics' with the exception that the quasi-sample can be assumed to have a significant calibration error function in the region of interest-曰. For A, if a standard sample can be assumed to exhibit a sharp change in reflectance due to changes in sample characteristics, the exact characteristics of the known standard sample are not required. Before the reference sample I can be used to evaluate the results of the calibration process, it needs to be mathematically constructed—a method for quantitatively evaluating CEF based on the combination of CEF and reference sample reflectance spectra. In an embodiment of the invention, this is typically done in the following manner. First, calculate the derivative of the measured reflectance spectrum. This is used to reduce the coupling between the CEF and the actual reflection spectrum of the multi-test sample t and more emphasis on the &quot;sharp&quot; rate of 120526.doc -22-200809180;; 1 (probably the contribution of CEF) instead of Emphasize (from the characteristics of the reference sample pre-measured =. Next, calculate the absolute value of the derivative and obtain the number of the 〃1 in the integral t of the integral value. 叙-τ J m M is the negative value of the bar and avoids the reflection by the reference sample The contribution of the light derivative. After the integration is completed, the result of the initial slave procedure can be quantitatively evaluated. The secret method can feed back the integral value to the algorithm, which is iteratively related to the initial hypothesis of the quasi-sample characteristics. Recalculate the CEF and re-integrate the value in order to minimize its value. When the minimum has been reached, the &quot;actual&quot; characteristic of the standard sample has been determined and thus its &quot;actual&quot; reflectivity has been determined. The reflectometer is calibrated and the measurement of the unknown sample is performed. After reviewing the data presented in Figures 8 to U', a further understanding of the steps involved in this method can be achieved. Figure 8 illustrates the use of ι〇〇 〇〇 assumed &quot;thickness The result of the measurement performed on the appropriate reference sample after the quasi-10000 A Si〇2/Si standard sample. The reference sample (which is adjusted to the core calibration X (4) spectrum is apparently sharp structure for calibration. The result of 1 〇A error. The signal 8 〇 2 shown in Figure 8 is the measured spectrum obtained from the reference sample. This signal is the product of the reflectance of the reference sample and the CEF spectrum caused by the inaccurate calibration. In this case, the CEF signal is substantially concomitant with the reference sample reflectance signal, and is apparently mainly present at the shorter wavelength in νυν. In this example, since the CEF signal is mainly present in the νυν region and reference reflection in this same region The rate is essentially non-characteristic, so this occurs. The derivative of this spectrum is presented in Figure 9. Not surprisingly, the reference reflection 120526.doc -23- 200809180 rate product derivative signal 902 still resides in the VUV region of the spectrum. Next, the absolute value of the trace is calculated prior to integration, which ultimately produces a quantitative measure of the accuracy of the calibration. This integral is then passed back to an iterative procedure, the iterative procedure The “standard sample” hypothesis, thickness, and recalculate the CEp/reference reflectance product integral until the value is minimized. For the 10,000 Α SiOVSi standard sample (with or without noise added to the system), the sensitivity curve of Figure 10 is presented. The value of the CEF/reference reflectance product integral as a function of the "hypothetical" thickness. Curve 1002 illustrates the value of the CEF/reference reflectance product integral including the presence of 0.5% of the noise component, while curve 1004 shows no noise information. Since the inspection of the data is obvious, even if there is 〇·5% of the noise component in the original reflectance data, the integral is very sensitive to the small error of the π hypothesis n thickness of the Si〇2 layer. Needless to say, the minimum value of the Cef/reference reflectance product integral is achieved when the "what if" thickness value matches the "actual" thickness of the standard sample. After the iterative process is completed, the &quot;actual,&quot; characteristics of the standard sample are determined and the instrument is accurately calibrated. At this time, as shown in Fig. 11, the CEF function assumes a value of one at all wavelengths, and subsequent measurement of the reference sample produces its true reflection spectrum 丨1〇2. An exemplary detailed description of this calibration procedure is outlined in flowchart 1202 of Figure 12 which presents the mathematical relationships involved in calculating the absolute reflectivity of an unknown sample. As shown in step 1204 of Figure 12, the assumed reflectance of the standard sample is first calculated using hypothetical identities of standard samples that are expected to exhibit significant calibration error characteristics in a given spectral region. The intensity from the standard sample is recorded in step 12〇6. In step 12〇8, the source intensity profile is calculated using the assumed reflectance of the standard sample. Next, the intensity of the reference sample from the pre-120526.doc -24-200809180 period exhibiting substantially smooth reflection characteristics in the same spectral region is recorded in step 121. Next, the reflectance of the reference sample is calculated in step 1212. Next, the reflectance of the reference sample can be expressed according to the equation of step 1214. The absolute value of the derivative of the reference sample reflectance spectrum can then be calculated in step 1216. Next, the integral of the absolute value of the derivative is calculated in step (2) 8. Next, an iterative adjustment to the hypothesis regarding the characteristics of the standard samples is performed and the assumed reflectance of the standard samples is recalculated in step 1220. Control is passed back from step coffee to step 1214 until the integral value is minimized and thus the actual characteristics of the standard samples are obtained during the process from step 1220 to step 1222. The source intensity profile is calculated using the actual reflectance of the standard sample in step 1222. Next, the intensity of the unknown sample is recorded in step 1224. Finally, the reflectivity of the unknown sample can be calculated and expressed according to the equation of step 1226. &quot;hypothetical &quot;characteristics and limited in the same way) complex refractive index, composition, heat* The skilled artisan will recognize that there are many other ways to quantify the CEF signal in this way to make it available for feedback back Iterative procedure, the iterative procedure is designed to minimize the value of the standard sample by adjusting the &quot;hypothesis, the characteristics of the standard sample. 'Although the above discussion has considered the thickness of the standard sample to be accurately determined during the calibration process &quot;hypothesis&quot; Features, but those skilled in the art will progress to understand that many of the other characteristics of the standard sample can also be considered as deterministic. Such characteristics may include (but not porosity and surface or interface roughness. These characteristics may be determined independently during the weighting order period, or in some instances 'these characteristics and other characteristics may be determined simultaneously. In the case, Cole&gt; j imposes additional mathematical steps to enhance the effectiveness of the calibration procedure. b) The presence of 120526.doc -25-200809180 significant noise in the measured reflectance data recorded from the reference sample is advantageous. This may be to filter the original data before or after the derivative of the original data. Although there are many suitable smoothing filters in the prior art, the Savitzky-Golay filter is particularly suitable for this application because it usually preserves the spectral characteristics of the original data. Width and position. Additionally, in some cases, limiting the wavelength range (integrating the wavelength range) to further emphasize the contribution of the CEF signal has proven to be beneficial. It will be apparent to those skilled in the art that the present invention is readily Contribute to many implementation modes. A particularly advantageous approach would be to integrate the reference sample into the reflectometer so that it is not expensive Use the reference sample in U.S. Application No. 10/668,644 (applied on September 23, 2003, which discloses a vacuum ultraviolet reference reflectometer) and US application No. iOAO9" No. 26 (at 2〇〇4) This method is described in detail in the application Serial No. 3, the disclosure of which is incorporated herein by reference. An example of a technique. Figure 12a provides a broadband reflectometer system 34 as described in more detail in Figure 34 of the U.S. Application Serial No. 1/9,9,126, filed on Jan. 4, 2011. The system 34 includes a plurality of sources 3201, 3203, and 3 302 and corresponding plurality of spectrometers 3214, 3216, and 33 04 as desired. Inverted mirrors FM-1 to FM-4 and corresponding windows W-3 to W -6 can be used to select various sources and spectrometers. As shown, mirrors Μ 1 through M-5 are used to direct the beam. Sample 3206 can be positioned in sample beam 32 10. Reference beam 32 12 is also provided. A beam splitter BS is provided and the baffles S-1 and S-2 select which beam to use. Sealing chambers 3202 and 32 in the environment Various optics and samples may be included in 04 such that measurements in the VUV bandwidth are available. 120526.doc -26- 200809180 As shown in Figure 12A, a sample beam (or channel) 321 is provided to sample 3206 A measurement is provided. A reference beam (or channel) 3212 is provided to reference the system. Typically the 'reference beam is configured to provide a mechanism indicative of environmental or other system conditions. The reference beam can be configured to provide a sample beam with the sample beam The beam path and beam conditions of similar environmental conditions, however, the reference beam does not encounter the sample 3 2 0 6 °. In the case of operation with the calibration techniques described herein, the standard sample can be placed in Figure 12A. The sample is at 32〇6. However, a separate reference sample need not be placed at the location of sample 32〇6 (although such utilization of a separate reference sample placed at the location of sample 3206 can be used). The only thing is 'the entire reference beam 3212 path can be seen as a reference sample." For example, σ, beam splitter BS, mirror M_4, window w_2, and mirror (ie, 'between sample path and reference path The cumulative effect of different components can be considered as forming a ''reference sample''. If the combined effect of the optical elements provides a relatively smooth, uncharacteristic reflection spectrum in the spectral range of the sense/feel, Such utilization of the entire beam path of the reference sample is obtained. It will be appreciated that those skilled in the art will appreciate many other methods of using calibration techniques and the calibration techniques described herein are not limited to the mechanical groupings referenced herein. Not shown, but the reflectometer system 34A can include a processor, a battery, other electronics, and/or software for calibrating the system in accordance with the registration techniques provided herein. Processors, computers, other electronics The device and / or software can be constructed with a reflectometer optical hardware - or can be a separate stand-alone unit that, together with the reflectometer optical hardware, is configured to allow for calibrated reflections The present invention provides a number of advantages. One advantage is that it provides a technique by which the uncertainty associated with a commercially available film standard sample may be too large to be utilized by the 120526.doc -27-200809180 忒 technique. Method Accurate calibration makes it possible to accurately calibrate VUV reflectance measurements. As a result, the need for reflectometer tool users to purchase, maintain, and recalibrate expensive standard samples is completely eliminated. Furthermore, the present invention allows for the use of standard samples or The exact characteristics of the reference sample achieve very accurate calibration results without prior knowledge. This ability is particularly useful, g] 4 real 35 can be expected to have samples of the sample t experienced # &amp; time

A small change in the function (due to natural growth mechanisms or contaminants). While the present invention is particularly well suited for calibrating VUV reflectance measurements, the present invention can also be used to calibrate reflectance measurements from other spectral regions. In these examples, 'using other standard samples (which can be expected to produce significant cef signals in the spectral region of interest) can be advantageous. Another advantage of the present invention is that it requires (four) times. Level reference instruments, which greatly reduce the cost and complexity of the system. Once the reflectance data has been recorded from the calibrated reflectometer, the beta reflectance is typically sent to the processor unit, which is then reduced at the processor unit via an analysis algorithm. These algorithms associate the optical data of the sample, such as reflectivity, with other characteristics of the sample (eg, film thickness, complex refractive index, beta-free porosity, surface or interface roughness, etc.), which can then be measured and / or monitor these features. Data reduction is usually accomplished using some form of phenanthrene equation combined with the optical properties of a plurality of models. Regardless of the specific mode of the material when reducing the Bellow set, the larger goal is to use the number 120526.doc -28-200809180 j· expression to describe the measured data so that it can be obtained through the iterative optimization process and the sample characteristics. Some parameters related to (as discussed above). That is, the measured data set is compared with the expression (4) data (4) determined by the set of parameters related to the nature of the sample. The difference between the measured data set and the calculated data set is minimized by iteratively adjusting the parameter values until a sufficient agreement is achieved between the two data sets.胄 Always use the &quot;fitness&quot; (GOF) parameter to quantify this difference. There are numerous mathematical expressions used in the prior art for calculating G0F. Most of these techniques are based in part on the determination of the difference between the measured and calculated spectra. While these methods are generally applicable and reasonably locate the "abnormal region" of the absolute minimum in the parameter space, they typically exhibit shortcomings at the minimum at convergence, especially in the measured data. In the case of a quasi-increase. As calculated for the 10,000 A Si〇2/Si test sample, Figure 13 presents a prior art GOF expression (known to those skilled in the art as the &quot;chi-square&quot; advantage function) sensitivity curve 13〇2. Obviously, this standard advantage function provides an efficient way to locate the general area of the film &quot;actual&quot; thickness because it exhibits a relatively smooth line shape with a well-defined minimum 'however, more The sensitivity of the function near the minimum value is significantly reduced, and the point is better illustrated in Figure 14 'Figure'. The sensitivity curve of Figure 13 is presented in the case of the presence of noise in the measured reflectance data (4) Expand Figure 1402. It is obvious in the core material of Figure 14 that 1% of the noise remaining in the original reflectance data will significantly reduce the advantage of the pure minimum (four) order can be 120526.doc -29- 200809180 converges on the test sample "actual "The ability in thickness. Therefore, there is a need to develop an excellent method of determining the actual &quot;thickness&quot; when the program has been roughly positioned near the answer. Another preferred embodiment of the invention provides this capability. That is, this embodiment provides a highly sensitive convergence measurement that can be combined with an appropriate minimization procedure to effectively reduce the measured reflectance, & yielding a higher level of accuracy, followed by The results can be achieved using only conventional techniques. Although the present invention is designed to be utilized in conjunction with conventional merit functions, the present invention completely replaces the utilization of such methods in some instances. A general overview of one embodiment of the data reduction technique described herein is presented in flowchart 1502 of Figure 15, in which the mathematical relationships involved in an iterative data fitting procedure associated with the use of a reflectometer to measure unknown samples are presented. . A first step 1504 in the process is to obtain an absolute reflectance spectrum of the unknown sample using a precisely calibrated reflectometer. In step 丨5〇6, once this spectrum has been recorded, it is convenient to calculate the "expected" reflection characteristics of the sample using the initial hypothesis about the physical properties of the sample. After mastering the two spectra, as shown in the equation of step 1508 , determining the "expectation, the spectrum and the "measured" ratio of the spectrum 〇 this ratio referred to herein as the measurement error function (mef) is essentially similar to the previously described CEF. Although the two functions are related" Suppose the ratio of the dataset to the actual ''dataset', but the MEF is slightly easier to evaluate because it is not coupled to the reflectance of the reference sample. That is, during the minimization period, the CEF is evaluated by examining the reference sample reflectance spectra. The MEF is evaluated by examining the reflectance of the unknown sample itself. 120526.doc • 30 - 200809180 Before the MEF (or reflected light ratio) can be used to evaluate the results of the minimization procedure, the appropriate merit function must be constructed again. After the method adopted by the CEF, the next step in the flowchart 152 is to calculate the absolute value of the derivative of the MEF as shown in step 丨5丨〇. This is used to emphasize the MEF. Sharp spectral characteristics 'The spectral characteristics are primarily caused by wavelengths near the absorption edge of one or more materials containing unknown samples. At this point, as shown in step 1512, the absolute value of the derivative is calculated and then the resulting function is integrated. As before, the absolute value of the derivative needs to be obtained before the integration in order to actively obtain positive and negative values. Once the integration is completed, it is possible to quantitatively evaluate the result of the reduction process. More specifically, as shown in step 1514, An iterative process of adjusting the hypothesis about the characteristics of the unknown sample and recalculating the expected reflection spectrum of the unknown sample may occur. After recalculating the expected reflection spectrum, control passes to step 1508 and steps 1508-1514 are repeated until the integral is minimized. The value is now again obtained from the actual characteristics of the unknown sample and control passes to step 1516 where the actual characteristics of the unknown sample are provided as an output. Note that this technique is for "hypothesis, reflection spectrum and" measurement &quot; fixed offset between reflection spectra is not sensitive. That is, it cannot be effectively used to reduce self-contained Long-wavelength reflectance measurements collected from samples of thin films (ie, thin enough without causing significant interference effects) are not possible because of the sharp spectral characteristics that are obtained from this. Fortunately, in the νυν region (V, all film samples show some form of sharp structure in their reflection spectrum, which is caused by interference or absorption effects. To better prove the effectiveness of this method relative to the habit The superiority of the performance of the chi-square method, FIG. 16 presents the development sensitivity calculated by the embodiment of the present invention for the si〇〇〇〇2/si 120526.doc-31-200809180 test sample of the same 1A of FIG. Curve 1602. Comparing the results in these two figures, it is shown that the present invention is less affected by the chi-square method than the influence of the chi-square method in the original reflectance data. This confirms that the present invention provides a more efficient measurement of the fitting minimum and thus the "actual" thickness of the film for the optimization procedure. The improved effect proves that the present invention is capable of more accurate and repeatable results than would be possible with conventional methods, at least when the "hypothetical" thickness values are substantially, practically, near the thickness. Studies of larger parameter spaces have demonstrated the best use of the present invention in some cases in combination with prior art methods. After examining Figure 17, the reason for this becomes apparent. Figure 17 presents a sensitivity curve 1702 calculated for a 10,000 A Si〇2/Si sample using the present invention plotted over a wider "hypothetical" thickness value range. Although in "actually, the MEF integral value at the thickness can be clearly distinguished from the integral value at all other ''hypothetical" thicknesses, the sharp nature of the line shape of the MEF integral makes it computationally difficult to fit. Therefore, it is more efficient to start searching for the minimum using the merits based on the chi-square, and then, once a significant convergence is reached, transition and use the present invention to continue searching for the "actual" minimum. In this concept, the use of the present invention represents a high resolution mode of reflectometer operation. In other instances, the benefits provided by the present invention may be appreciated without the use of conventional chi-square methods. An example of this is to measure a 100 Å Si〇2/Si sample with 1% of the noise present in the measured reflectance data. In this case, the global search performance of the present invention is comparable to that of the standard chi-square method. A comparison of the sensitivity curves presented in Figure 18 provides evidence. For example, as shown in Fig. 18, the sensitivity curve 18〇2 of the standard chi-square method is compared with the sensitivity curve 1804 using the MEF technique according to the present invention. Although the two functions show a relatively smooth line shape, it is noted that the effect of 1% of the noise in the reflectance data is already evident in the chi-square results. 19 and FIG. 20 show the SiOVSi sample covering 100 people calculated by using the MEF technology of the present invention (sensitivity curve 1902 of FIG. 19) and the chi-square method (sensitivity curve 2〇〇2 of FIG. 20), respectively. The expansion sensitivity curve of the 4 a region near the thickness. The comparison of these two graphs demonstrates the advantageous performance of the present invention in this case. Therefore, data measurement can be obtained by using a fitting program, which is included At least a portion of the program of the spectrally driven fit program is not solely dependent on the amplitude driver (which typically incorporates a difference calculation). More specifically, the measurements can be obtained by using the presence of sharp, narrow spectral features. In an embodiment using a spectral driver, the ratio of the expected reflected light of the sample being measured to the actual reflected spectrum of the sample being measured. The techniques provided herein use a ratio of expected to actual values rather than based on expectations. The difference between the value and the actual value. The derivative of this ratio can be used to emphasize sharp spectral characteristics. These spectrally driven techniques are characterized by sharp spectral features (eg, film-like This is especially useful in the spectral region of the sharp features typically exhibited in the VUV region. Thus, a convergence technique is provided which can advantageously use the absorption edge effect of the disclosed materials. In this way, sharp spectral characteristics are advantageously used ( For example, 'which is caused by interference or absorption effects' to more accurately determine the minimum value of the data indicative of the actual measurement. The merit function presented in this disclosure can therefore be absorbed by the material being measured 120526.doc -33- 200809180 The characteristics are driven, where the area containing large absorption (absorption edge) changes due to small changes in sample characteristics is emphasized. The data reduction technique can use a two-step method. In this embodiment, the first (4) amplitude can be used. The low resolution step of the drive fitting program is provided to provide a &quot;rough&quot; measurement. Then (4) a high-resolution step such as a spectrally driven fitting program that advantageously uses the presence of sharp spectral features to then provide &quot;fine&quot; Measurement. In one of the methods used in this technique, by using a difference-based technique (such as the chi-square &quot; advantage function) A low resolution method is used to obtain a roughly 1 measurement, and then a more accurate determination of the actual measurement can be obtained by using a technique based on the spectral drive ratio in the region of focus initially identified by the low resolution technique. The techniques provided can be viewed as dynamic weighted results for regions with sharp spectral features. For example, 'About the sharp spectral edges present in the vuv range' can be considered as a weighting function that emphasizes VUV and DUV and longer wavelength data, where sharp spectral characteristics may not be expected for a given sample, are deliberately ignored. Additionally, the process can be weighted so that only measured data that can reasonably be expected to contain useful information can be included. It is dynamic because the decision process can be repeated after each iteration (which one should be considered). While the examples presented herein have used this technique to aid in accurate measurement of film thickness, it will be apparent to those skilled in the art to measure other material properties including, but not limited to, complex refractive index, composition, porosity. Other preferred embodiments of the invention may be used in the same manner as surface, interface roughness, and the like. In addition, although the examples provided herein have been specifically addressed to si〇2/si 120526.doc -34 - 200809180 many:: Class: 疋 Obviously 'the technology can be equally utilized to quantify the == method provided. Examples of such stacks include a base yUMSKVSiN stack or a film on a substrate (4) 4:: "The high sensitivity level provided by the present invention is primarily due to the light in the - or more of the materials comprising the samples: edge In the case of the material, the α-substantial change of the present time with a small change in the characteristics of the sample, although these characteristics are usually located in the spectral region, but due to minor changes in the physical properties of the sample being studied, it is expected to be substantially In the case of sharp features, this technique can be applied at longer wavelengths. Those skilled in the art will recognize that 'there are many other ways to quantify the MEF number in this way so that it can be used to feed back to the iterative process. In the method, the pass-through program is designed to minimize its value by adjusting the "what if" characteristic of the measured sample. In addition, it will be easy to understand that in some cases τ, additional mathematical steps can be performed to enhance the performance of the measurement procedure. It will be appreciated that as described above, a calibration technique is provided which may include utilizing two calibration samples during the calibration process. In addition, the technique allows calibration even if there is a change between the actual and hypothetical characteristics of at least one of the calibration samples. Additionally, the above techniques include a calibration technique in which the ratio of the reflected intensity measurements from the first calibration sample to the reflected intensity measurements from the second calibration sample is used (for example, Iref as shown in Figure 12). /Ieal). 120526.do, -35. 200809180, under the condition that there may be changes in the sample and system variations and offsets, the ratio of the intensity of the reflections from the multiple samples and the intensity of the reflections from the samples can still be achieved in various ways. calibration. For example, as described above, with two = quasi-samples, the #_ calibration sample in # has a sharp light (7) characteristic in the wavelength of interest and the second sample is in the wavelength region of interest compared to the first sample: No features. In another example where two calibration samples are used, the ratio of the intensity of the reflection from the calibration sample to the intensity of the reflection from the second calibration sample can be used, and either of the two calibration samples need to be relatively absent. Features. In this embodiment, as described in more detail below, only the reflection characteristics of the sample at the desired wavelength are required to be relatively different. In this technique, it is then believed that the reflectance data for each sample has been relatively self-contained. The technique described above with reference to the first sample and the relatively uncharacterized second sample is an example of using two calibration samples having relatively different reflection characteristics, however, as described below, none of the calibration samples may be used for the spectrum. Features the technology. More specifically, even in the absence of absolute reflectance calibration, the ratio of reflectance from two samples can be measured via the measured intensity, since Equation 3 is from each sample in a short time from each other. Measuring the intensity 'the environment or instrument offset will not play a significant role, therefore, Equation 3 is caused by the fact that during the two measurements, the incident intensity I. will not change. This ratio can be analyzed using standard film regression analysis to extract the same film parameters (n, k, thickness, interfacial roughness, etc.) as determined by the absolute reflectance of a single sample. However, unlike the case of a single intensity, the change in the measured ratio between different measurements is due to the variation of the sample itself, 120526.doc • 36- 200809180

The example calibration sample described is provided only to show an example. It will be appreciated that the techniques disclosed are provided to aid in understanding and other calibration samples and thicknesses can be used. Therefore, in order to provide an illustrative description of the calibration technique, a modified &amp; calibration sequence can be utilized in conjunction with a 1000-input (8) calibration #. By measuring the intensity of the two samples, the ratio of the intensities can be analyzed to take the oxide thickness of the two samples. The thickness determined for the bare Si calibration sample can be fed back to the calibration procedure of Equation 2 to (4) more accurate absolute reflectivity. 21A, 21B, 22A, and 22B show a relationship between a native Si〇2/Si calibration sample (sample 1, corresponding to R!) and a nominal 1000 A SiOVSi calibration sample (sample 2' corresponds to R2). A comparison of simulated reflectance ratios. Figures 21a and 21B show the effect of increasing the native Si〇2 thickness contrast ratio Ri/Ri. As shown in Fig. 21A, the reflectance ratio Rz/Ri is provided for wavelengths up to 1 〇〇〇 nm, and Fig. 21B is a developed view for the same ratio of wavelengths between 1 〇〇 nm and 400 nm. In Figs. 21A and 21B, Si〇2 for 10, 20 and 30 A in curves 21〇6, 21 04 and 2102 respectively shows a curve of the influence of the change of the native oxide on the sample 1 (R〇). The main effect of the thickness of the native Si〇2 is to increase the ratio in VUV because the reflectance is reduced. 120526.doc -37- 200809180 Compared with this, the effect of increasing the thickness of si〇2 of l〇〇〇A is to change The maximum and minimum interference of the long wavelength. More specifically, FIG. 22A and FIG. 22B illustrate the sample 2 (the SiO 2 /Si, loio A of 1〇〇〇a) for the sample 1 (the native oxide of 2〇a). The effect of the change of si〇2/Si&amp;1〇2〇a si〇2/Si). More specifically, curves 22〇2, 22〇4, and 22〇6 show sample 2 (1000 A Si, respectively) The effect of the change of 〇2/Si, Si〇2/Si of 1〇1〇A and SiO2/Si of 1020 A (Fig. 22A shows the unfolded view from the wavelength of 100-400 nm). Therefore, two samples can be considered The thickness (the same thickness and the same thickness) has been de-faced and the thickness of each can be extracted from the standard analysis of the contrast ratio measurement. In addition, the absolute reflectance standard can be used without In this case, the specific thickness is extracted from the ratio data. Because this ratio is the same regardless of the system or lamp offset (assuming a fairly fast, continuous measurement of intensity or sample 丨 and sample 2), it is observed in the ratio over time. The difference will correspond to the change of the actual sample. Figure 21 and Figure 22 illustrate that if the sample characteristic is si〇2 thickness, the thickness variation on each sample can be determined. Then, the sample 2 is detected in this way. The thickness of the native oxide layer can be used to improve the quality of the absolute calibration using the sample. Note that if one of the calibration samples does remain constant, the reflectance change of the other samples can be inferred directly from the ratio change. However, in practice, The mechanism used to calibrate the sample offset is usually the accumulation of the contaminant layer on the two samples, so this will usually not be the case.

This technology can still be used. For example 'organic contaminants or based on 矽. For the above-mentioned Si calibration sample 120526.doc -38- 200809180, it is sufficient to explain the fact that the growth of pollutants will reduce the J and 6 pairs of reflectivity, so the precise description of the pollutants is not a real gift. However, the most accurate calibrations included the different contaminant layers on the two samples. Relative reflectance measurements can be used to determine a better optical description of the accumulation of contaminant layers on a calibration sample and incorporate information into the calibration procedure. The film structure in the above examples may be the contaminant layer of the sample w/the original sicvsi and the contaminant layer of the sample 2/1000 A of SiO 2 /Si, in the phase 斟 g u t曰

The thickness of the contaminant layer is determined during long relative reflectance measurements. This will not only produce a more stable absolute reflectance calibration, but will first produce a more accurate absolute reflectivity. An illustration of how the accumulation of contaminant layers may affect the reflectance ratio for different amounts of contaminants is provided in Figures 23A and 23B. The film structure is sample ^ A^Si02/SiA#^2^^t4^/10〇〇

SiOW. Figure 23 shows a comparison of the thicknesses of two different contaminant layers for the mouth 2〇 and 30 people in curves 23〇2, 23() 4 and 23()6, respectively. Note that since the optical properties of the depleted layer are actually different from the optical properties of Si〇2, the properties are decoupled from the properties shown in Figs. 21 and 22. In other words, all three parameters can be determined simultaneously from a single ratio measurement: native oxide thickness #oxide thickness and contaminant layer thickness. As previously stated, the determined thickness can be fed back into the calibration procedure of Equation 2. Obviously, in this case, if only the contaminant layer is expected to change, either or both of the oxide thicknesses may be fixed to a previously determined value. In addition, it may be reasonable to assume that the same amount of soil layer is accumulated on two samples to constrain the analysis. As long as the reflection characteristics of the sample are sufficiently different (hence, for all ' ratios are not exactly 1)' this type of measurement can be used to analyze the sample and 120526.doc -39- 200809180 will not affect the uncertainty of the calibration standard. For example, t, the relative reflectance measurement can be used to obtain a modified optical description of si〇2 at the vuv zone towel as compared to the observed ratio.

In the example described above, the two samples are formed from the same material (the native skd2 on Shi Xi and the thick Si〇2 on Shi Xi). The advantage of using the same material for two samples can be: same-contaminant Can be produced on the surface of two samples. The use of samples with different surfaces can cause differences in the film of contaminants produced, making the contaminant layer more difficult to characterize. However, it will be appreciated that the techniques described herein can be used where the samples have different materials. Further 'attention' the above examples provide a technique in which the characteristics of Sample 1 (native oxide sample) are determined and then the data is used as a calibration standard. Alternatively, however, the characteristics of sample 2 can be determined and the data used can be used as a calibration standard. In the implementation of the fiscal, it is more advantageous to calibrate the sample to make a thicker Si〇2 sample, because any residual error is more likely to be displayed in the form of an artifact in the vicinity of the interference value of the Xian 2 interference. Generally, the film structure can be any structure. For such structures, sufficient information is known to be able to construct the model ratio, and any of the samples can be used for further calibration. As is known in the art, calibration samples can be constructed in any number of ways: Sample 1 and Sample 2. In one embodiment, each of the two samples can be formed on the same substrate. For example, Figure 24 illustrates a possible mechanical embodiment of a calibration procedure in a reflectometer system, two oxide liners of different thicknesses (such as the sample in the above example! and sample 2) as an overview.塾2 is formed on a semiconductor wafer or mounted on a semiconductor wafer chuck. However, the techniques described herein are not limited to any particular mechanical embodiment of the concepts provided. 120526.doc -40.200809180. The technique described above thus provides two samples, which have a relative reflectance ratio R^/R from two samples of / φ L with relatively different reflection characteristics. Using this technique, changes in calibration standards can occur as the time passes, while still providing accurate calibration. ~ j implements these technologies in the form of evenings. An exemplary calibration procedure is described with reference to Figures 25 and 26, however, it will be appreciated that other steps and procedures may be used while still utilizing the techniques described herein. As shown in FIG. 25, an exemplary technique is provided in which, assuming a first calibration sample, the original 35 reflectance is similar to the ratio between the reflectance of the first calibration sample and the reflectance of the second calibration sample, thereby calibrating Reflectometer. More specifically, in step 2502, the hypothetical reflectance of the sample 丨 is calculated using the hypothetical recognition of the calibration sample 预期 (expected calibration sample 1 will exhibit substantial calibration error characteristics in a given spectral region). Next, in step (4), the intensity of the standard sample 1 is recorded. Next, in step 25〇6, the source intensity profile is calculated using the assumed reflectance of the calibration sample 1. In step 25〇8, the intensity of calibration sample 2 (expected to exhibit a sample substantially different from the reflection characteristics of calibration sample 1 in the same spectral region) is recorded. Next, the reflectance of the calibration sample 2 is counted at step 2510. Next, the ratio of the reflectance of the calibration sample 1 to the reflectance of the calibration sample 2 is expressed as a ratio in step 2512. Next, as shown in step 25 14 , the dummy model for calibrating the sample i and the calibration sample 2 is constructed and expressed as a reflectance ratio. In step 25 16 , the regression algorithm and the merit function can be used to iteratively adjust the assumptions about the characteristics of the calibration sample 1 and the calibration sample 2 and recalculate the hypothesis mode 120526.doc •41-200809180 type reflectance' until the calculated The difference between the reflectance ratio and the reflectance of the model ratio is minimized and thus the "real", sample 1 and sample 2 are obtained. Next, in step 25丨8, using the calibration sample i, the actual , the reflectance recalculates the heterogeneous intensity profile. In step 252, the intensity of the unknown sample can then be recorded, and in step 2522, the reflectance of the unknown sample is shown as shown. Another exemplary calibration flow chart. As shown in Figure %, a simplified process can be used in which the reflectance ratio can be directly formed using the intensities from the two samples (compared to the technique of Figure 25, in the technique of Figure 25, Calculating the assumed reflectance of the same sample from the hypothetical recognition of one of the samples) As shown in Fig. 26, in step 26〇1, the intensity of the calibration sample is recorded. In step 2603, the recording is recorded. The intensity of quasi-sample 2 (expected to be in the same spectral region | a sample different from the reflectance characteristic of calibration sample i), then, as shown in step 2605, the calibration is based on the intensity recorded from sample 样本 and sample 2 The ratio of the reflectance of sample i and calibration sample 2. Next, ./ as shown in (d) 201, the pseudo- and pull-up type used to calibrate sample 1 and calibration sample 2 can be constructed and expressed as a reflectance ratio. In step 2616, the regression and the merit function can be used to iteratively adjust the assumptions about the characteristics of the calibration sample and the calibration sample 2 and recalculate the hypothetical model reflectance, ^ to the calculated reflectance ratio and the ratio of the model. The difference between the rates is minimized and thus the "actual" characteristics of samples 1 and 2 are obtained. Next, the source of the &quot;actual&quot; reflectance of the calibration sample 1 is recalculated in [=8]. In step 2, the intensity of the unknown sample can then be recorded, and in step 2622, the reflectance calculated by the unknown sample is indicated as 120526.doc -42.200809180. It should be noted that 'from analyzing or otherwise discussing the ratio in Equation 3, by first calculating from a standard thin film model (see, for example, H. G Tompkins and WA McGahan, Spectroscopic Ellips〇metry and Reflectometry: a Userfs Guide, John Wiley) And Sons new York, (1999), the method of calculating the individual reflectivity, and the calculation of the ratio is convenient. However, it should be apparent that the thin film model can be easily re-presented to apply directly to the ratio 1 &quot;12 which is mathematically and conceptually equivalent. Figure 27 provides a further illustration of the concepts described in Figures 23 and 26. Figure 27 shows reflectance ratios for extracting oxide and contaminant layer thicknesses from two calibration samples, one calibration sample with thin oxide (sample 1} and one calibration sample with thicker ~1 〇〇〇A Oxide (Sample 2). The surface of each sample also has a small amount of contaminant layer accumulated during use in the VUV reflectometer. The reflected intensity is collected from the two calibration samples and the reflected intensity is used to form the measured reflectance. Ratio. Construct model ratios and allow oxide and stain layer thickness to vary between regression points (4). _ return analysis minimizes the error between the calculated ratio and the measured ratio. For this analysis, Si Si02 and contamination are considered. The optical properties of the wood layer are known and fixed (the optical properties of Si〇2 and contaminants are determined from previous analyses of the reflectance ratio, and the optical properties utilized in Figures 23 and 23B are slightly different). The optimum thickness for the best fit between the calculated ratio and the measured ratio is 6.06 A for thick oxide samples and Si〇2 for _·〇A and 9·49 A for thin oxide samples. Contaminants and 1 8·62 entered (10). At this time, the absolute reflectance of the two 120526.doc -43. 200809180 samples is known, and the optimization parameters can be used together with the optical properties of each layer and the standard film model. The reflectivity of the present. If the model ratio is calculated during the optimization by calculating the heart and 1 , the reflectivity of the optimized sample 丨 and 2 can be obtained at the end of the fitting process without further calculation. The reflectance of the film of 2 thickness but no contaminant is shown for the sample 图 in FIGS. 28A and 28B and the thin 〇 2 caused by the analysis of FIG. 27 is shown for the sample 2 in FIGS. 28C and 28B. The reflectance of the sample and the thick si 〇 2 sample (curves 2802 and 28 〇 6 have contaminants, and curves 2804 and 2808 have no contaminants). As shown, Figure 2 is an expanded version of one of the curves of Figure 28a. Similarly, Figure 28 is an expanded version of the portion of the curve of the graph. It is apparent from these figures that as even a small amount of contaminant builds up, the reflectance can vary significantly, especially in the area of the right oxide sample in the region below the Duv wavelength. _ is used to assume constant The reflectivity, the lower material, the error in the area below the DUV will be significant. This effect is even greater as the Essence/Wood is produced on the sample. At the end of the analysis illustrated in the figure Any of the measured intensities of the samples can be used with the appropriate (with contaminant) reflectance from Figure 28 to determine the source intensity profile.

A small ^~dan interface has a more complex Si,2/Si system by analyzing the intermediate interface of the effective media model combination of uncontaminated calibration samples, and the ratio is pre-characterized Si〇2 and intermediate 120526 .doc -44- 200809180 Layer thickness will be feasible. The α-left #* ruler procedure will be used to determine the characteristics of the stain (as it accumulates), 疋 疋 物 层

〇 ^ T 5 is S1〇2 and the interface characteristic is 邱p A and its thickness and optical properties are fixed during the analysis of Wang 4 known as H丄 sheep. Bake or wash away the empty Bayi's, W Dingshipu knife dyes (AMC) by white peony samples, or chemistry in the extreme conditions (i is also a 匕, will also remove some 3 丨02 material), can get uncontaminated samples. In addition to the intermediate / ^ T interlayer, ultra-thin oxides (which include bismuth) are native oxides and antimony compounds on the stone stalks, which may have optical properties different from those of thicker cerium oxides. And Huang Yiyi ^

This can also be considered in the reflectance pull type.

The Sl〇2/Si calibration sample is step-by-step to improve the alignment accuracy. A convenient regression procedure for analyzing the reflectance ratio is WH Press, s. A. Teukolsky, WT Vetterling AB p F1, followed by Numerical Recipes in C: The Art of Scientific CompuUn,, Han Erqi (Cambridge University Press) The well-known algorithms described in (CambHdge, ma: 1992)), however, will recognize that any number of methods known in the art can be used to optimize or otherwise extract membrane parameters. In some cases, regression algorithms and membrane models may even be unnecessary, as it is sometimes possible to more directly infer the change in reflectance of one or more of the calibration samples from changes in the reflectance ratio. The described method need not be limited to two calibration samples and can be generalized to include multiple weight samples. For example, 'the third sample (sample 3) may be a thick (eg, 3000A) fluorinated town MgFVSi sample' and simultaneously analyze the ratios R2 /r 1 and R3/R1 to sample 1 (sample 1 and sample 2 may have The various layers of the film structure similar to the example of Figure 27 provide further constraints. Perform calibration to determine 1〇 120526.doc -45- 200809180

During the period 'the intensity of samples 1, 2 and 3 will be measured within the time scale, where 1 〇 is approximately constant' for the measured data to form the ratio R2/r1&amp;r3/r1, and the regression analysis is used to extract all three simultaneously The thickness of the film and contaminant layer of the sample. In other words, the regression minimizes the error between the measured R2/R1 and R3/R1 and the calculated R2/Ri and R3/R1 by optimizing the parameters utilized in the calculated ratio. In implementing one of these concepts, the analysis can use a common generalization of the Levenberg-Marquardt program for multiple sample analyses, in which case the 'non-linear chi-square merit function can be written as: N2\Σ /=1 R2 measured

^ i,calculated J N3iΣ R3Έ J j,measured R3Έ ^ j,calculated Equation 4

Where private i and j are incident conditions (usually wavelengths), and N21 is the total number of data points included for each ratio. Multiple ratios typically consist of the same pupil range of /I and consist of the same number of measured data points, but this is not strictly required. Typically, each ratio can cover a different spectral range and the ratio does not have to consist entirely of the same number of measured data points. In Equation 4, ~ and 1 are estimated uncertainties for the measured reflectance ratio, which may depend on the human incidence condition. Since the characteristics of the sample i are common to the two ratios, the analysis pass f is basically used to determine the fit of the sampler characteristic by reducing the number of parameter sets that can result in the measured ratio. Additional constraints are provided. Next, the actual absolute reflectance Rcal=Ri is calculated using the optimized parameters of Sample 1, and the 反射g γ + 利用 is used to calculate the different .n/IUai. Additional constraints on the sample can assist in determining the thickness of multiple types of contaminants that can be present at the same time, or assist in addressing the contaminant layer of the uneven 120526.doc -46- 200809180. The ratio R3/R2 can also be added to the analysis. This concept can be extended to multiple samples consisting of any combination of nominal materials. 29A to 29L illustrate the effects of accumulation of contaminant layers on samples 1, 2 and 3 of the previous examples. The simulations in Figures 29A through 29L utilize the same optical characteristics as in Figures 27, 28A, and 28B for SiO 2 , Si, and contaminant layers, 4 and obtain MgF 2 * learning characteristics from available literature. 29A and 29B illustrate the ratio of sample 3 to sample 1 (contaminants having 1〇, 2〇, and 3〇A on each sample) as curves 2902, 2904, and 2906, respectively (Fig. 29B is a portion of Fig. 29A). The expanded version of f % points). 29C and 29D illustrate the ratio of sample 2 to sample 1 (contaminants with 10, 20, and 30 A on each sample) as curves 2908, 2910, and 2912, respectively (Fig. 29, Fig. 29 (: part of Expanded version) Figure 29E and Figure 29F illustrate the ratio of Sample 2 to Sample 1 (these samples only show the effect of the accumulation of pollutants at 10, 20 and 30 A on Sample 1) as curves 2914, 2916 and 2918 (Figure 29F is an expanded version of a portion of Figure 29E. Figure 29G and Figure 29H illustrate the ratio of sample 2 to sample 1 respectively (these samples only show the effect of pollutant accumulation on 10, 20, and 30 A on sample 2) Curves 2920, 2922, and 2924 (Fig. 29H is an expanded version of a portion of Fig. 29G). Figures 291 and 29J show the ratio of sample 3 to sample 1 respectively (the samples are only shown • 1 , 20, and 30 on sample 1) The effect of the accumulation of contaminants in A is illustrated as curves 2926, 2928, and 2930 (Fig. 29J is an expanded version of a portion of Fig. 291). Figures 29K and 29L show the ratio of sample 3 to sample 1 respectively (the samples only show samples) 3 The effects of pollutant accumulation on 10, 20 and 30 A are illustrated as curves 2932, 2934 and 2 93 6 (Fig. 29L is an expanded version of a portion of Fig. 29K). Figure 2 9 A to Fig. 2 9 The simulation in L shows 'different pollutants affecting different spectral regions of different ratios 120526.doc -47- 200809180. On sample 1 The effect of the accumulation of contaminants tends to increase the ratio in the region below the DUV and in the DUV region, while the cumulative effect on the thicker film tends to increase the interference amplitude. There are different thicker films (8丨〇2 and MgFO have Helping to further constrain the possible membrane structure that can lead to similar ratios. The combined effect from the analysis of these ratios is at the same time the decoupling of the various parameters that are determined. Figures 29A-29L illustrate an example, but as described above, Even smaller decoupling is possible in the case of multiple samples, which, for example, allows for more precise simultaneous determination of multiple types of contaminant membranes. A method is discussed by which to derive for contaminant layers (such as The optical properties of the contaminant layer utilized in Figures 23A and 23B. These steps can be performed to obtain the initial thickness of Si〇2 and the intermediate layer and the optical properties of the contaminant layer. The optical characteristics can be used to improve the quality of the calibration procedure (actually by using a similar procedure to determine the contaminant optical properties for the simulation hypotheses in Figures 23A and 23B and Figure 27.) Additionally, once these characteristics are determined, the calibration samples are The ratio can be used to determine that all other predetermined characteristics (such as muscle and interface thickness and optical properties and contaminant optical properties) are known and fixed in determining the thickness of the contaminant layer during calibration. Pre-characterized with reflectance ratio The optical properties of the contaminants can be exemplified by: 1 Removal of airborne molecular contaminants (AMC) from thin Sl2 and 1k Si〇2 samples. For example | ‘Using hot plates, vuv pre-exposure, chemical pre-cleaning, sifting removal and pre-growth of native si〇2 layers or some combination of these technologies. 120526.doc •48- 200809180 2 Record the intensity ratio h/h of the sample (and therefore record the reflectance ratio R2/Ri). The reflectance ratio is analyzed to predetermine the thickness of the thick oxide layer and the native oxide layer. The t/Si intermediate layer may be included in the analysis of two samples, +. Any features considered to be known during the analysis (such as Si and Si〇2 optical properties) will be fixed. 3 Allow AMC or VUV-induced contaminants to accumulate on the sample. AMC will naturally occur when the sample is stored in the environment. When in vuv light

Vuv contaminants can accumulate over time as the sample is repeatedly measured in the leaf volume tool. , 4 Measure the sample after the accumulation of contaminants. A new dispersion ratio is analyzed using a dispersion model with adjustable optical properties to determine the thickness and optical properties of the soil layer. The analysis can be constrained by the thickness and thin Si〇2 and intermediate layer properties previously determined (and now fixed). In addition, ratio data can be collected at various stages of contaminant growth to provide multiple ratios, each having a different contaminant thickness (multi-sample analysis), but additionally having common contaminant optical properties. Alternatively, if the same contaminant optical properties cannot be used to fit all of the multiple transcripts, additional complexity can be modeled assuming non-uniform shading (d), coarse sugar interface or surface. The thickness of the dye layer and the optical characteristics of the contaminant layer are analyzed during the Ik post-alignment procedure to determine the reflectance ratio of the one (or more) types of contaminants on the sample, which can then be used to guide the { The reflectivity of at least one of the samples. At school 120526.doc -49- 200809180, the period of time will usually fix the optical properties of the contaminant layer, &lt; reduce the number of unknown parameters. =,: Although this is a known method for pre-characterization in ratio measurement, it is not the only way. In particular, alternatives measure the interface thickness or obtain better light for the nominal film: Field, Sl2, MgF2, Si or even contaminant optical properties). When used, the optical parameters can be obtained from the literature. During the pre-characterization period, it is determined that the township &amp; order period will generally remain fixed, and it will generally only be expected to change the Pilgrim helmet. The specific membrane structure of the initial sample need not be limited

Sl〇2/Sl structure. This procedure can be generalized and induces contaminant growth on numerous samples rather than just two samples. It can also be noted that with regard to analyzing the reflectance ratio, in some cases, when the denominator reflectance approaches zero, the ratio can become u. In practice, this condition will be obvious 'because the ratio will tend to become very good^ in these cases, the spectral region where this occurs can be deviated from the analysis, and the inverse ratio is analyzed in those regions. Since the absolute reflectivity of all calibration samples is usually determined from the ratio analysis, and the calibration of either of the samples will in principle produce the same ", it is not necessary to calibrate the entire measurement wavelength range by 1 利用 with the only one. For example The sample 1 can be used to determine 1 对于 for a spectral region, while the sample 2 is used to calibrate the second spectral region. Further modifications and alternative embodiments of the invention will be apparent to those skilled in the art from this description. The present invention will be considered as illustrative only and is intended to teach those skilled in the art to practice the invention. It will be appreciated that the form of the invention as shown and described herein in the form of the disclosures of Embodiments of the present invention will become apparent to those skilled in the art, and equivalents may be substituted for the elements described and described herein and certain features of the invention may be used independently of other features. BRIEF DESCRIPTION OF THE DRAWINGS [Fig. 1 illustrates a prior art calibration and measurement flow chart for a reflectometer. Figure 2 illustrates a prior art detailed study for a reflectometer. And the measurement flow chart. Figure 3 illustrates the reflection spectrum from the ultra-thin Si〇2/Si sample.Figure 4 illustrates the calibration error spectrum of a 2〇8的2/8丨 sample generated for a series of assumed thicknesses. 5 illustrates an exemplary calibration and measurement flow diagram in accordance with an embodiment of the present invention.Figure 6 illustrates a calibration error spectrum of 8丨〇2/samples generated for a series of assumed thicknesses. A reflection spectrum of a wide frequency νυν mirror (# 1200) manufactured by Acton Research, Inc. Fig. 8 illustrates the product of the reference sample reflectance spectrum and the calibration error function of a 10000 A SiVOSi sample obtained from the measurement of an arbitrary reference sample. Describe the derivative of the calibration error function for the SiO 2/Si sample of 10000 A for the assumed thickness of looio A. Figure 10 illustrates the sensitivity curve calculated using the calibration error function integral of the 10,000 A Si〇2/Si standard sample. The reflectance of the reference sample utilized in the calibration procedure. 120526.doc -51- 200809180 Figure 12 illustrates an exemplary detailed calibration and measurement flow diagram in accordance with an embodiment of the present invention. An exemplary reflectometer system of the calibration concept of the present invention. Figure 13 illustrates a sensitivity curve calculated using a standard prior art advantage function of a 10,000-input Si〇2/Si sample. Figure 14 illustrates the measured reflectance data. An expansion sensitivity curve calculated using a 1 〇〇〇〇 person's 〇 2 / with a standard prior art advantage function of the sample in the presence of 1% noise. Figure 15 illustrates an exemplary embodiment in accordance with an embodiment of the present invention Detailed measurement flow chart. Figure 16 illustrates the expansion sensitivity curve calculated using the MEF integral of a 10000 A SiOV Si sample with 1% noise on the measured reflectance data. Figure 17 illustrates the sensitivity curve calculated using the MEF integral of the Si〇2/Si sample of loooo A. ^) Figure 18 illustrates the comparison of the sensitivity curves calculated using the MEF integral of the 1 〇〇 A SiC^/Si sample with the standard prior art merit function. Figure 19 illustrates the presence of 1% noise on the measured reflectance data • The expansion sensitivity curve calculated using the MEF integral of the 10 Å A SiOV sample. Figure 20 § shows the expansion sensitivity curve calculated using the standard prior art merit function of the 100 A SK^/Si sample in the case of the % reflectance data. 120526.doc -52- 200809180 Figures 21A and 21B illustrate plots of relative reflectance ratios for two calibration samples, with thinner oxides varying on one of the samples. Figures 22A and 22B illustrate plots of relative reflectivity of two calibration samples in which a thicker oxide varies over one of the samples. Figures 23A and 23B illustrate the relative reflectance curves of two calibration samples of contaminant layers having different thicknesses. Figure 24 illustrates an exemplary mechanical embodiment of two calibration samples. Figure 25 illustrates a flow chart of an exemplary technique for calibrating reflectometry using the reflectance ratio of two calibration samples. Figure 26 illustrates another flow diagram of an exemplary technique for calibrating reflectance measurements using the reflectance ratios of two calibration samples. Figure 27 illustrates the curve of a result of the reflectance ratio fitted from two calibration samples. A calibration sample has a thin oxide and a calibration sample has a thicker oxide. Figures 28A through 28D illustrate plots of the effect of contaminant layer reflectance on the reflectance of thin oxide samples and thick oxide samples. Figures 29A through 29L illustrate plots of reflectance ratios for various samples with accumulation of contaminant layers. [Main Component Symbol Description] 102 Flowchart 202 Flowchart 302 Reflectance Spectrum 304 Reflectance Spectrum 3 06 Curve 120526.doc -53- 200809180 308 Curve 310 Curve 502 Flowchart 602 Spectrum 604 Spectrum 702 Reflection Spectrum 802 Signal 902 CEF/Reference Reflectance Product derivative signal 1002 curve 1004 curve 1102 reflection spectrum 1202 flow chart 1302 sensitivity curve 1402 expansion chart 1502 flow chart 1602 sensitivity curve 1702 sensitivity curve 1802 sensitivity curve 1804 sensitivity curve 1902 sensitivity curve 2002 sensitivity curve 2102 curve 2104 curve 2106 curve 120526.doc - 54- 200809180 2202 Curve 2204 Curve 2206 Curve 2302 Curve 2304 Curve 2306 Curve 2802 Curve 2804 Curve 2806 Curve 2808 Curve 2902 Curve 2904 Curve 2906 Curve 2908 Curve 2910 Curve 2912 Curve 2914 Curve 2916 Curve 2918 Curve 2920 Curve 2922 Curve 2924 Curve 2926 Curve 2928 Curve 120526.doc - 55 - 200809180 2930 Curve 2932 Curve 2934 Curve 2936 Curve 3201 Source 3202 Environmentally dense Chamber ' 3 203 Source 3204 Environmental Seal Chamber 3206 Sample 3210 Sample Beam 3212 Reference Beam 3214 Spectrometer 3216 Spectrometer 3302 Source 3304 Spectrometer 3400 Broadband Reflectometer System ^ ./ BS Beam Splitter FM-1 ~ FM-4 Flip mirror • M_1 ~ M-9 Mask Sl~S2 Baffle W1 ~ W6 Window 120526.doc -56-

Claims (1)

200809180 1. 2. 3· j 4· 5. 6· The scope of the patent application · · The standard of the plate - the method of obtaining the reflectivity data, comprising: obtaining the reflectance data from a first calibration sample, from the first The weighted sample obtains reflectance data, wherein certain exact characteristics of at least one of the first calibration sample and the second calibration sample may be different from a plurality of hypothetical characteristics of the off-board quasi-sample, and wherein the first calibration sample is The second calibration sample has different reflection characteristics; and two: - based on the ratio of the data obtained from the first calibration sample to the data obtained from the second::: present to assist in calibrating the system. Reflectance data, the first calibration = quasi-sample collects the first set of r π ^ samples in - the first wavelength quasi-error function that needs to be calibrated, and from the second calibration sample collects 1 / rate stomach material 'this second calibration Compared with the standard sample, the sample has less spectral characteristics in the wavelength range. The method of claim 2, wherein one of the first-school alignment samples is thinner than the oxide-oxide, and the method 1 of claim 3 has a thicker oxide. The configuration and the wipes (4) 'calibration samples contain - SiCVSi: = two calibration samples contain, 2 / si structure. The method of Yue Yong Xiang 4, the basin of the ancient female 窜 窜: is - the original oxide film. The thinner oxygen on the calibration sample is self-methoded by the reflection from the first calibration sample. The reflectance data decoupling of the sample is as described in the method of [6], wherein the second calibration sample on the second calibration sample is 120526.doc 200809180, and the first calibration sample has a thicker oxide. . The method of claim 6 wherein the thinner oxide on the second calibration sample is a native oxide. 9. The method of claim 8, wherein the first calibration sample comprises a scavenging structure and the second calibration sample comprises a - si〇2/Si structure. A method of claiming a method wherein the first calibration sample has a thicker oxide than a thinner emulsion on the second calibration sample. The method of claim H), wherein the first calibration sample comprises a -sKvsi structure and the second calibration sample comprises a si〇2/Si structure. 12. The method of claim H), wherein the second calibration sample is a spectrally unspecified reference sample. The method of claim 10, wherein the reflection characteristics of the first calibration sample and the second calibration template have been decoupled from each other so as to be obtainable based on the A j quasi sample and the second calibration sample The reflected intensity data differs from the actual physical characteristics of at least one of the first calibration sample and the second calibration sample. 14. The method of claim 1, wherein the step of using further comprises: configuring a calibration procedure to provide a first set of reflectance data from the first calibration sample and based at least in part on the first set of reflectance data First calibration of one of the systems; and configuring the calibration procedure to use a second set of reflectance data from the second calibration sample. The second set of reflectance data has fewer features than the (four) set of reflectance data. κ, as requested by the method, wherein the resource obtained from the first calibration sample is 120526.doc 200809180 is the intensity data and the second degree data. And the data obtained from the second calibration sample is a strength data of the strong calibration sample Reflectivity. 16. The method of claim 15, wherein the method of calibrating a reflectometer is obtained from the intensity data of the first right and the second calibration sample, the method comprising: wherein the first provides a first calibration sample and one a second calibration sample, wherein the reflection characteristics of the quasi-sample and the second calibration sample are different; collecting the first set of data from the first calibration sample; collecting the second set of data from the second calibration sample; and using the first set of data A ratio of at least a portion of the second set of data to at least a portion of the second set of data to determine a characteristic of at least one of the first calibration sample and the second calibration sample such that reflectance data from an unknown sample can be calibrated. 19. The method of claim 18, wherein the first set of data obtained from the first calibration sample comprises intensity data and the first set of data obtained from the second calibration sample comprises intensity data. The method of claim 19, wherein the intensity ratio from the intensity data of the first calibration sample and the intensity data of the second calibration sample is obtained. The method of claim 20, wherein the source intensity profile is obtained by utilizing the reflectance ratio and wherein the reflectance of an unknown sample is calibrated by utilizing the source intensity profile. 120526.doc 200809180 22. As in the method of claim 20, calibrate a number of changes in at least _ of the sample. Wherein the first (four) first calibration sample and the second one will exhibit a number of hypothetical physical characteristics 23, 24, Ο such as the method of claim 2 2, the pot can be directly injected into the sample as the first priority sample and the At least one of the second sensed samples obtains a consistent reflectance, which is expected to exhibit a number of changes from a number of hypothetical physical properties. The moonman 23 goes to 'where the actual reflectance is obtained a source intensity profile and wherein the source intensity profile is used to calibrate the reflectance of an unknown sample by means of the sound intensity profile. 25. A method of claim 18, calibrating a number of changes in at least one of the samples. The first calibration sample and the second one will exhibit a number of hypothetical physical characteristics. 27. 27. As in the method of claim 25, the bean is finely praised by the eighth middle pre-J, the younger one, and the first The method of claim 25, wherein the method of claim 25, wherein a hypothetical reflectivity of the at least one of the calibration sample and the second reference sample is used to calculate a The initial source intensity profile 'expects at least one will exhibit several variations from its good assumed physical characteristics. 28. The method of claim 27, wherein the first calibration sample and the at least one of the second calibration sample are used - Calculating the actual reflexed source intensity profile by calculating the actual reflectivity, it is expected that the at least one will exhibit several changes from its several hypothetical physical characteristics. 29. If the method group information of claim 18 has been derived from it, The second set of data from the first second calibration sample of the first calibration sample decouples 120526.doc 200809180 a quasi-sample and the obtained intensity data of the second calibration sample to calculate the first calibration sample And the actual physical property of at least one of the two calibration samples. 35. The method of claim 33, wherein: the ratio of 5 is based on the intensity obtained from the first calibration sample and obtained from the second calibration sample A ratio of the intensities, , and two, is obtained by using the ratio to obtain a source intensity profile, and by using the source intensity profile to calibrate the reflectance of an unknown sample. 36. The method of claim 33, wherein: / = = 4 - calibration sample - assumed reflectivity and the first set of data to calculate an initial source intensity profile, using 4 first group of lean material and the initial source intensity profile Obtaining a reflectance of the second candidate sample, using the hypothetical reflectivity of the Haidi-weighted sample and the second calibration sample It. The ratio of the reflectance of the transmitted reflectance is determined to determine the actual characteristic of the first calibration sample, and is obtained by using the reflectance of one of the first calibration samples of the temperature - recalculated 37. 38. 39. = intensity (4) 'The reflectivity is based on the determined actual characteristics. The method of claim 36, wherein the actual characteristic of the first calibration sample is a material thickness. The method of claim 33, wherein a ratio of reflectance is obtained from the intensity data of the first calibration sample of the first calibration sample. The method of claim 38, wherein a 120526.doc 200809180 source intensity profile is obtained by using the reflectance ratio and the reflectance source intensity profile of the complex sample is calibrated - unknown 4 〇 · as requested in claim 38, Gu, Tu # The first calibration sample and the second variation are expected to be in the calibration sample. v exhibits from a number of hypothetical physical characteristics, such as the method of claim 4, to calibrate at least the quasi-sample and the second one to serve an actual reflectivity, it is expected that at least the previous day V is derived from Assume several changes in physical properties. 2. The method of item 41, wherein the reflectance of an unknown sample is calibrated by using the actual reflectance to obtain -:, contour and wherein the source intensity rim is utilized. 43. As in the method of claim 33, calibrating a number of changes in at least one of the samples. Wherein the first calibration sample and the second one are expected to exhibit a plurality of hypothetical physical properties 44. The method of claim 33, wherein the first calibration is compared to the thinner oxide on the second calibration sample The sample has a thicker oxide. The method of claim 44, wherein the first calibration sample comprises a structure and the second calibration sample comprises a SiO 2 /Si structure. 46. The method of claim 45, wherein The thin oxide on the second calibration sample is a native oxide. 47. A method for analyzing reflectometer data, comprising: providing a first reflectometer sample and at least a second reflectometer sample, wherein the first The optical response characteristics of a calibration sample and the optical response characteristics of the second calibration sample are different; 120526.doc 200809180 The first set of optical reaction data is collected from the first reflectometer sample; the second set is collected from the first reflectometer sample Optical reaction data, and using the first group in a manner independent of the intensity of an incident reflectometer used in collecting the first set and the second set of optical response data The second set of optical response data determines at least one characteristic of at least one of the first reflectometer sample and the first reflectometer sample. 48. The method of claim 47, wherein the characteristic is the first reflectometer A change in a physical property of at least one of the sample and the second reflectometer sample. The method of claim 48, wherein at least one of the first reflectometer sample and the second reflectometer sample is The method of claim 47, wherein the first reflectance meter sample and the second reflectance meter sample are all calibration samples. The method of claim 47, wherein the determining step further comprises: Using a ratio of at least a portion of the first set of optical response data to at least a portion of the second set of optical response data. 52. The method of claim 5, wherein the ratio is based on the first sample and the The second sample measures the optical intensity. 53. The method of claim 51, wherein the use of the ratio allows for determining a change in the at least one characteristic. 54. A method of calibrating a reflectometer, comprising: Providing two or more calibration samples, wherein the reflection characteristics of the calibration samples are different from each other; each of the calibration samples is harvested - a set of measured poor materials; and 120526.doc 200809180 : determining, by a combination of the measured data independent of the source intensity, the _ characteristic of at least __ of the registered samples such that the reflectance data from an unknown sample can be calibrated. 55. The method of claim 54, wherein - or a plurality of the calibration samples have a layer of contaminants, wherein the contaminant layers are determined by analyzing the measured data. - or multiple features. The method of item 54, wherein the data collected from the calibration samples includes intensity data. 57. According to the method of claim 56, the intensity data of the quasi-sample of the 嬅海 4杈 sample or a plurality of reflectance ratios. 58. The method of claim 57, wherein - or more of the calibration samples have a plurality of contaminant layers, wherein one or more of the contaminant layers are determined by analyzing one or more of the reflectance ratios or Multiple features. 59. The method of claim 57, wherein the source intensity profile is obtained by utilizing the reflectance ratios and wherein the reflectance of the sample is calibrated by utilizing the source intensity profile. 60. The method of item 59, wherein the source strength is obtained by first analyzing the reflectance ratios using a thin film model and analyzing to adjust - or more of the - or more of the calibration samples. One of the analysis results is used for the channel Τ, °; to derive an absolute reflectance of one or more of the calibration samples, wherein the absolute reflectance is used to obtain the source intensity profile via a λ, J: by # 〇 - by RT using the determined source intensity profile ^r = VIg to calibrate - the unknown sample - reflectivity. 6 as in the method of claim 56 - where at least the calibration samples are expected - 120526.doc 200809180 The exhibition does not exhibit a number of changes in its assumed physical properties. 62. The method of =61, wherein at least one of the calibration samples is subjected to an actual reflectance, and the at least one combined hypothetical physics is expected A number of variations of the characteristics. The method of claim 62, wherein the reflectance of the unknown sample is calibrated by using the actual reflection to convert the degree profile and the t by the source intensity profile. · = the method of item 54, which It is expected that at least one of the calibration samples will exhibit several variations from its several hypothetical physical characteristics. 65. The method of claim 64, wherein all of the hypothetical physical properties are expected to vary. I. (4) 66. The method of claim 64, wherein an initial source intensity gallery is calculated using the at least one of the plurality of calibration samples, and the pre-(four) to 乂-person exhibits a plurality of hypotheses from the method 66. 'The use of the at least one or two. The actual reflectance of ten different to calculate a ', two expected at least - the calibration sample spread intensity (four), a number of changes from the right dry hypothesis physical characteristics 68. = item 54 ' The method for determining the parameters to be determined is the combination of the calibration samples from the 69. The method of claim 54 provides, 'the present or more than two calibration samples 70. Method, the first sample of the first calibration sample having a first calibration sample having a first film and having a first or a plurality of calibration samples having a first film A third calibration sample having a second thicker film, the first thicker film and the second thicker film being different films. The method of claim 70 wherein the first calibration sample comprises a thin si. '(4): The calibration sample contains a thicker film, and the third calibration sample contains a thicker MgF2 film. The method of the monthly solution 71, wherein the thin film 2 on the first calibration sample is a primary oxidation The method of claim 72, wherein the _ or the plurality of contaminant layers are explicitly modeled, and the portions of the calibration samples are - or more, wherein the combination is utilized, And a method of determining one or more of the contaminant layers 73, wherein a Si〇2/Si interface layer is explicitly modeled as part of one or more of the calibration samples. The method of the member 74, wherein the thickness of the Sl2/Si interface layer is pre-characterized and remains fixed during the calibration. 76. 77. 78. 79. The method of claim 73, wherein a MgF2/Si interface layer is explicitly modeled as part of the calibration sample. The method of,,, wherein the thickness of the MgF2/Si interface layer is pre-characterized and remains fixed during the calibration. The method of claim 69, wherein - or more of the calibration samples have - or a plurality of contaminant layers, wherein one or more of the contaminant layers are determined by analyzing the combination of the measured data Features. The method of claim 69, wherein the resource collected from the calibration samples includes intensity data, 120526.doc -11 - 200809180 'monthly method 79, wherein the intensity data from the calibration samples is obtained by one or Multiple reflectance ratios. The method of claim 80, wherein one or more of the calibration samples have one or more contaminant layers, wherein the contaminant layers are determined by analyzing one or more of the reflectance ratios One or more characteristics. 82. The method of claim 8, wherein the source intensity profile is obtained by using the reflectance ratios and wherein the reflectance of an unknown sample is calibrated by utilizing the source intensity profile. The method of claim 82, wherein the source intensity wheel is obtained by first analyzing the reflectance ratios using a thin film model and regression analysis to adjust - or more characteristics of the calibration samples.靡, and the results of the analysis in the basin are used to derive - or a plurality of I absolute reflectances in the calibration samples, where the absolute reflectance is used to derive the source intensity profile via Ig = WRj, where by Ca, Using one of the determined source intensity profiles, one of the unknown samples is calibrated for reflectivity via R=Ir/I〇. &quot;. The method of claim 80, wherein at least one of the calibration samples is expected to exhibit a number of variations from a number of hypothetical physical characteristics thereof.方法. The method of claim 84 wherein a plurality of changes in physical properties are assumed for at least one of the calibration samples. From the method of claim 85, the method of claim 85, the center of the source of the wheel and its center is used to obtain the reflectance of a sample with the actual reflectivity. Calibrating with the source intensity rim - unknown 87. The method of claim 69, wherein at least one of the calibration samples is expected to exhibit a number of variations from a number of hypothetical physical properties. 88. If = method of claim 87, wherein all such calibration samples are expected to be false. There are also several changes in physical properties. 89. The method of claim 87, wherein the at least one of the plurality of calibration samples is used: assuming a reflectance to calculate an initial source intensity rim, the eve is expected to exhibit a number of variations from a number of hypothetical physical properties thereof. 9. The method of claim 89, wherein the at least one of the calibrated samples is calculated using a different actual reflectance - the recalculated source intensity porch, the at least - calibrated sample is presented from a number of hypotheses Several changes in physical characteristics. 91. The method of claim 69, wherein the data from the calibration samples are combined in a manner that effects of the parameters of the to-be-faced shirt. - A method of calibrating a reflectometer, wherein the reflectometer is operated at a wavelength comprising at least some wavelengths below a deep ultraviolet (duv) wavelength, the method comprising: providing a plurality of calibration samples, at least some of which are The reflection characteristics are different; the data set is collected from the calibration samples, including at least some of the intensity data collected for wavelengths below the wavelength of the wavelengths and a combination of the ones of the sources using the data sets - The reflectivity of at least one of the calibration samples is determined to assist in calibrating the reflectometer at at least some of the wavelengths included below the DUV wavelength. 93. The method of claim 92, wherein one or more of the calibration samples have one or more contaminant layers, i φ AP &amp; eight f, i is analyzed by the right stem data set of the group 120526 .doc -13- 200809180 Combined to determine one or more characteristics of these contaminant layers. The method of claim 92, wherein the plurality of reflection characteristics of the calibration samples have been combined with each other (four) such that at least - I of the calibration samples can be calculated based on the obtained intensity data of the calibration samples. Several actual physical characteristics. 95. The method of claim 92, wherein: the combination of the data sets comprises a plurality of ratios of a plurality of intensities obtained from a calibration sample such as Yanhai, obtaining a source intensity profile by using the ratios, and 96, by utilizing the The source intensity profile is used to calibrate the reflectance of an unknown sample. The method of claim 92, wherein: calculating the initial source intensity profile using the assumed reflectivity and the corresponding data set of the first calibration sample of the calibration samples, using the corresponding data set and the initial source intensity a vertex to obtain a reflectivity of one or more of his calibration samples, eight using the assumed reflectance of the first-calibrated sample and the other calibration samples = the middle or the more of the obtained ones - The ratio is used to determine an actual characteristic of the divisor quasi-sample, and a reflectance of one of the first calibration samples is used to obtain a re-leaf source intensity profile based on the determined actual characteristic. - 97. If the method of claim 96 is used, the actual property of the quasi-sample of the 6 hai dynasty is one material thickness. 98. If the method of claim 92 is used, the bean material is good—the strength of the strength of the sample from the special school is obtained from the right dry reflectance ratio. 120526.doc -14· 200809180 99. The method of claim 98, wherein 嗲笙p 住 丄 杈 杈 杈 杈 杈 杈 杈 杈 杈 杈 杈 杈 杈 杈 杈 杈 杈 杈 叙 叙 叙 叙 叙 叙 叙 叙 叙 叙 叙 叙 叙 叙 叙 叙 叙 叙 叙 叙^ ^ ^ , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , 。 The method of claim 98, wherein the reflectivity of the sample is calibrated by (iv) a (b) reflectance ratio source intensity profile and wherein the source intensity profile is utilized. Only the method of claim 98 is not contemplated, wherein one of the calibration samples is expected to exhibit several variations from its several hypothetical physical characteristics. 102. As in the method of claim 1 , 1, one of the calibration samples for the or (d) calibration is expected to be reversed (four) to expect that or the calibration samples will exhibit several changes in the physical properties of the null hypothesis. /, the method of claim 2G2, wherein the original intensity rim is obtained by using the actual reflectance and wherein the reflectance of the known sample is calibrated by using the source intensity profile. The method of claim 92, wherein - or - of the plurality of calibration samples exhibits a number of variations from a number of hypothetical physical properties thereof. 1〇5. The method of claim 92, wherein three or more calibration samples are provided, such as the method of requesting 〇5, the three (four) three samples of the towel comprise a first calibration sample having a film. A second calibration sample and a third C7 having a second thicker film, the first thicker film and the second thicker film being different films. 107. The method according to claim 106, wherein the first calibration sample comprises a thin Si〇2, the second calibration sample comprises a thicker SK)2 film, and the third calibration is 120526.doc -15- 200809180 The sample contains a thicker MgF2 film. The method of claim 107, wherein the first film is a native oxide. 109. The method of claim 1, wherein the one or more contaminant layers are explicitly modeled into three or more portions of the calibration sample, and wherein the combination is utilized by the material dragon group. Determine the contaminant layer: - or multiple characteristics. 110. The method of claim 109, wherein the Sl〇2/Si interface layer is unambiguously modeled as part of the calibration sample. 1 1 1 • The method of claim 1 1 ,, the thickness of the basin 8 r 4 Si〇 2/Si interface layer is pre-characterized and remains fixed during this calibration. 112. According to the method of claim 1-9, a MgFVSi interface layer is explicitly modeled as part of the calibration sample. 113. The method of claim 112, wherein the thickness of the /, T 4 MgF / Si interface layer is pre-characterized and remains fixed during the calibration. 114. According to the method of claim 92, one or more of the 1 φ 呤 ρ ρ 荨杈 荨杈 具有 具有 具有 具有 具有 具有 具有 具有 具有 具有 具有 八 八 八 八 八 八 八 八 八 八 八 八 八 八 八 八The combination of the right dry data sets determines one or more characteristics of the contaminant layers. The method of U-92, wherein the reflection characteristics of the calibration samples have been combined from each other such that at least one of the calibration samples can be calculated based on the intensity data obtained from the material of the calibration sample. Several actual physical characteristics. The method of claim 92, wherein: the combination of the data sets comprises a plurality of intensity ratios 120526.doc -16 - 200809180 obtained from the calibration samples, by using the ratios to obtain a source intensity profile, The reflectance of an unknown sample is calibrated by using the source intensity profile. The method of claim 92, wherein: using a hypothetical reflectivity of the -to-calibration sample of the calibration sample and a data set corresponding to °H to calculate an initial source intensity profile, by using the correspondence The data set and the initial source intensity wheel of the other calibration sample towel - or more _ reflectivity, ^ using the 4th - plate quasi-sample hypothetical reflectivity and - or more of the other calibration samples j The ratio of the obtained reflectance is determined to determine an actual characteristic of the first reference sample, and the first calibration sample reflectance is used to obtain a re-counted source intensity rotation 'the reflection (4) based on the The method of determining the opening 118.: Γ: Γ, wherein the actual characteristic of the first calibration sample is a material thickness. 1 1 9 • A number of reflectivity ratios are obtained for such strong materials from the calibration samples of the requirements of 9 2 $古,土, , , / , 八中. Find the intensity of the shell 1 2 0 · If the item 1 1 9 $ ancient, i, with m, the calibration sample - or more of the 5 々 々 layer, which is determined by analyzing the reflectance ratio Such as the contaminant layer - or more (four). As early as the sheep and 12 1 · If the request item 1丨9 $ t,, soil ^, Γ, choose to go 'where the source intensity profile is obtained by using the reflectance ratio and 1 again, 9 use the source intensity The contour is used to calibrate the reflectivity of an unknown sample. Yiqian 122. If the request is made, the one of the calibration samples is expected to be one of 1205-1. Physical characteristics • The method of requesting item m, which can be: -. - Actual reflectivity, which is expected to result in several changes in the physical properties of the hypothesis. The method of claim 2, wherein the reflectance of the known sample is obtained via the -source intensity profile and wherein the _"profit" μ actual reflectance is utilized. The source intensity rim is used to calibrate - not as in the method of claim 92 'Where the _ material calibration sample—or more will exhibit several changes in the physical properties of the hypothesis. — A method of analyzing reflectometer data, comprising: for three or more reflectometer samples, The optical response characteristics of the samples are different from each other; (4) each of the isoreflectometer samples collects optical response data; and by using the optical response data sets to be independent of the collection of the optical response data sets The method of using the intensity of the human reflectance meter to determine at least one characteristic of at least one of the reflectometer samples, such as the method of claim 26, wherein the characteristic is at least one of the reflectometer samples A method of claim 127, wherein the method of claim 127, wherein at least one of the reflectometer samples is a calibration sample, such as the method of claim 128, wherein The radio sample is all a calibration sample. The method of claim 126, wherein the determining step further comprises: using a ratio of a plurality of combinations of the plurality of optical response data sets. 120526.doc • 18- 200809180 131. 132. The method of item 130, wherein the ratios are based on the optical intensity measured from the reflectance samples. The method of claim 13 wherein the use of the ratios allows for determining a change in the at least one characteristic. 120526.doc -19-