TW201350839A - Metrology tool with combined X-ray and optical scatterometers - Google Patents

Abstract

Methods and systems for performing simultaneous optical scattering and small angle x-ray scattering (SAXS) measurements over a desired inspection area of a specimen are presented. SAXS measurements combined with optical scatterometry measurements enables a high throughput metrology tool with increased measurement capabilities. The high energy nature of x-ray radiation penetrates optically opaque thin films, buried structures, high aspect ratio structures, and devices including many thin film layers. SAXS and optical scatterometry measurements of a particular location of a planar specimen are performed at a number of different out of plane orientations. This increases measurement sensitivity, reduces correlations among parameters, and improves measurement accuracy. In addition, specimen parameter values are resolved with greater accuracy by fitting data sets derived from both SAXS and optical scatterometry measurements based on models that share at least one geometric parameter. The fitting can be performed sequentially or in parallel.

Description

Metering tool with combined X-ray and optical scatterometer [Cross-Reference to Related Applications]

U.S. Provisional Patent Application No. 61/644,050, filed on May 8, 2012, entitled "Scatterometry Metrology Apparatus With X-Ray And Optical Capabilities", filed on May 8, 2012, filed on May 8, s. The title of the application is "Priority of the U.S. Provisional Patent Application No. 61/669,901, the entire disclosure of which is incorporated herein by reference. The subject matter of each of the U.S. Provisional Patent Applications is hereby incorporated by reference in its entirety.

The described embodiments relate to metering systems and methods, and more particularly to methods and systems for improved metrology accuracy.

Semiconductor devices such as logic and memory devices are typically fabricated by applying a sequence processing step to a sample. The various features of the semiconductor device and the various structural levels are formed by such processing steps. For example, lithography involves, among other things, the creation of a semiconductor fabrication process on a semiconductor wafer. Additional examples of semiconductor fabrication processes include, but are not limited to, chemical mechanical polishing, etching, deposition, and ion implantation. A plurality of semiconductor devices can be fabricated on a single semiconductor wafer and then the plurality of semiconductor devices can be separated into individual semiconductor devices.

The metrology process is used at various steps during a semiconductor fabrication process to detect defects on the wafer to promote higher yields. Optical metrology technology offers the potential for high processing power without the risk of sample damage. Several optical metrology based techniques including scattering and reflectance measurements and associated analysis algorithms are typically used to characterize the critical dimensions, film thickness, composition, and other parameters of the nanostructure.

Traditionally, scattering measurements have been performed on targets consisting of thin films and/or repetitive periodic structures. Such film and periodic structures generally represent actual device geometry and material structure or an intermediate design during device fabrication. As devices (eg, logic and memory devices) move toward smaller nanoscale sizes, characterization becomes more difficult. Devices incorporating complex three-dimensional geometries and materials with a variety of physical properties create characterization difficulties. For example, modern memory structures are typically three-dimensional structures that make it difficult for optical radiation to penetrate to the high aspect ratio of the underlying layer. In addition, an increase in the number of parameters required to characterize a complex structure (eg, a FinFET) results in an increase in parameter correlation. Therefore, the parameters of the characterization target are often not reliably coupled to the available measurement. In another example, opaque high k (dielectric constant) materials are increasingly employed in modern semiconductor structures. Optical radiation typically does not penetrate the layers constructed from such materials. Therefore, measurement using a film scattering measurement tool such as an ellipsometer or a reflectometer becomes more and more challenging.

In response to these challenges, more sophisticated optical tools have been developed. For example, tools have been developed that have multiple illumination angles, shorter and wider ranges of illumination wavelengths, and more complete information acquisition from self-reflecting signals (eg, in addition to more conventional reflectance or elliptical measurement signals) Mueller matrix element). However, such approaches do not reliably overcome measurement and measurement applications (eg, line edge roughness and line width roughness) with many advanced targets (eg, complex 3D structures, structures less than 10 nm, structures using opaque materials) Measurements) The basic challenges associated.

In one example, a grazing incidence small angle x-ray scattering (GISAXS) is combined with an x-ray reflectance measurement (XRR) for surface layer characterization of a film, as issued on May 17, 2005 and transferred. It is proposed in U.S. Patent No. 6,895,075, the entire disclosure of which is incorporated herein by reference. These techniques are sensitive to the surface but are not sensitive to buried structures or membranes beneath the surface. In addition, the spot size of the probe beam is greatly increased due to the shallow angle of incidence employed in such techniques. While large spot sizes can be mitigated using, for example, apertures or blades, this results in undesired reductions in processing power and increased measurement time.

Future metrology applications are attributable to ever-increasing resolution requirements, multi-parameter correlations, increasingly complex geometries, and the increasing use of opaque materials to challenge metrology. Therefore, methods and systems for improved CD measurements are desired.

The present invention presents methods and systems for performing critical dimension measurements. These systems are used to measure structural and material properties associated with different semiconductor fabrication processes (eg, material composition, structure, and dimensional characteristics of the film, etc.).

In one aspect, a single metrology tool performs both optical scattering and small angle x-ray scattering (SAXS) measurements on one of the test areas of a sample. The SAXS measurement of combined optical scatterometry is a measurement tool with increased measurement capability due to the complementary nature of SAXS and optical scatterometry. SAXS is capable of measuring geometric parameters (eg, pitch, critical dimension (CD), sidewall angle (SWA), line width roughness (LWR), and line edge roughness (LER)) of structures less than 10 nanometers. In addition, the high energy of x-ray radiation essentially penetrates optically opaque films, buried structures, high aspect ratio structures, and devices that include many thin film layers. Optical scatterometry is capable of measuring pitch, CD, film thickness, composition and dispersion for many different structures.

In another aspect, parameters using the combined SAXS and optical scatterometry techniques can be improved by identifying common model parameters that can be mathematically sequenced or parallel analyzed using data sets derived from SAXS and optical scatterometry. Accuracy and accuracy. Using a variety of metrology techniques to measure the shared parameters reduces the correlation between the parameters and improves the measurement accuracy.

In yet another aspect, SAXS and optical scatter measurements performed on a plurality of different out-of-plane orientations of a planar sample (eg, a semiconductor wafer) increase the accuracy and accuracy of the measurement parameters. Measuring one of the samples at a plurality of different angles results in an enhanced data set corresponding to one of the locations. Using a deeper and more diverse data set to measure parameters also reduces the correlation between parameters and improves measurement accuracy.

The foregoing is a simplification, generalization and omission of the details of the invention, and therefore, it should be understood by those skilled in the art that the invention is only illustrative and not limiting. Other aspects, inventive features, and advantages of the devices and/or procedures described herein will be apparent in the non-limiting embodiments set forth herein.

100‧‧‧Combined metering system/combination metering tool

101‧‧‧ samples

102‧‧‧Inspection area

110‧‧‧x light lighting system

111‧‧‧Liquid metal container

112‧‧‧Liquid metal collector

113‧‧‧Electronic beam source

114‧‧‧Electronic optics

115‧‧‧x optical optics

116‧‧‧x photodetector

117‧‧‧x light beam

118‧‧‧Electronic flow

119‧‧‧ liquid metal jet

120‧‧‧Optical lighting system

121‧‧‧ Optical illumination source

122‧‧‧Optical illumination optics

123‧‧‧ Optical detector

124‧‧‧Signal/output signal/measurement data/measurement optical signal

125‧‧‧x optical radiation

126‧‧‧Output signal/measurement data/measurement x-ray signal

127‧‧‧ Optical illumination beam

128‧‧‧Optical radiation

130‧‧‧Computation System / Beam Controller / Computer System

131‧‧‧ processor

132‧‧‧ memory

133‧‧‧ busbar

134‧‧‧Program Instructions

136‧‧‧ command signal

137‧‧‧Command signal

140‧‧‧Sample Positioning System

141‧‧‧Edge clamp chuck

142‧‧‧Rotary actuator

143‧‧‧ Peripheral framework

144‧‧‧Linear actuator

145‧‧‧ motion controller

146‧‧‧ coordinate system

150‧‧‧Model Building and Analysis Engine

151‧‧‧Geometry model building module

152‧‧‧Geometric model

153‧‧‧x optical response function building module

154‧‧‧Optical response function creation module

155‧‧‧x optical response function model

156‧‧‧Optical response function model

157‧‧‧Fitting Analysis Module

160‧‧‧vacuum chamber

161‧‧‧vacuum window

162‧‧‧vacuum environment

170‧‧‧ sample parameter values

180‧‧‧ memory

1 is a diagram illustrating one of a metering system 100 configured to combine x-ray and optical metrology in accordance with the methods described herein.

2 is a diagram illustrating one of a model building and analysis engine 150 configured to parse sample parameter values based on x-ray and optical metrology data in accordance with the methods described herein.

3 is a diagram illustrating one of the x-ray detectors 116 of a combined metering system 100 included in a vacuum environment 162 that is separate from the sample 101.

4 is a flow chart illustrating one exemplary method 200 for simultaneously performing optical scattering and small angle x-ray scattering (SAXS) measurements on a test region of a sample.

5 is a flow diagram illustrating one exemplary method 300 for determining sample parameter values based on one of an x-ray response model and an optical response model that share at least one common geometric parameter.

Reference will now be made in detail to the preferred embodiments embodiments The present invention presents methods and systems for performing critical dimension measurements. These systems are used to measure structural and material properties associated with different semiconductor fabrication processes (eg, material composition, structure, and dimensional characteristics of the film, etc.).

In one aspect, a combination metrology tool performs both optical scattering and small angle x-ray scattering (SAXS) measurements on one of the test areas of a sample. One of the combined SAXS metrology and optical scatterometry tools is due to the complementary nature of SAXS and optical scatterometry to achieve increased measurement sensitivity and processing power. By way of non-limiting example, SAXS is capable of measuring geometric parameters (eg, pitch, critical dimension (CD), sidewall angle (SWA), line width roughness (LWR), and line edge roughness of structures less than 10 nanometers ( LER)). In addition, the high energy of x-ray radiation essentially penetrates optically opaque films, buried structures, high aspect ratio structures, and devices that include many thin film layers. By way of non-limiting example, optical scatterometry is capable of measuring the pitch, CD, film thickness, composition, and dispersion of many different structures.

SAXS and optical scatterometry for combined applications as described herein can be used to determine the characteristics of a semiconductor structure. Exemplary structures include, but are not limited to, FinFETs, low dimensional structures (such as nanowires or graphene), sub-10 nm structures, thin films, lithographic structures, germanium vias (TSV), memory structures (such as DRAM, DRAM 4F2). FLASH and high aspect ratio memory structure). Exemplary structural characteristics include, but are not limited to, geometric parameters (such as line edge roughness, line width roughness, hole size, hole density, sidewall angle, profile, film thickness, critical dimension, pitch) and material parameters (such as electronics) Density, grain structure, morphology, orientation, stress and strain).

1 illustrates a combination metering tool 100 that measures one of the characteristics of a sample in accordance with the exemplary methods presented herein. As shown in FIG. 1, the system 100 can be used to perform both optical scatterometry and SAXS measurements on one of the test areas 102 of one of the samples 101 disposed on a sample positioning system 140. In some embodiments, the inspection region 102 has a spot size of 50 millimeters or less.

In the depicted embodiment, metrology tool 100 includes a liquid metal based x-ray illumination system 110 and an x-ray detector 116. The x-ray illumination system 110 includes a high brightness liquid metal x-ray illumination source. A liquid metal jet 119 is produced from a liquid metal container 111 and collected in a liquid metal collector 112. A liquid metal circulation system (not shown) will lend The liquid metal collected by the collector 112 is returned to the liquid metal container 111. Liquid metal jet 119 contains one or more elements. By way of non-limiting example, liquid metal jet 119 comprises any of aluminum, gallium, indium, tin, antimony, and antimony. In this manner, liquid metal jet 119 produces x-rays corresponding to its constituent elements. In some embodiments, the x-ray illumination system 110 is configured to produce a wavelength between 0.01 nanometers and 1 nanometer. An exemplary method and system for producing high brightness liquid metal x-ray illumination is described in U.S. Patent No. 7,929,667, issued toK. .

An electron beam source 113 (e.g., an electron gun) produces an electron stream 118 that is directed by electron optics 114 to a liquid metal jet 119. Suitable electro-optical device 114 includes an electromagnet, permanent magnet or electromagnet for focusing the electron beam and directing the beam to the liquid metal jet, in combination with one of the permanent magnets. The superposition of the liquid metal jet 119 and the electron stream 118 produces an x-ray beam 117 incident on the inspection region 102 of the sample 101. The x-ray optics 115 shapes the incident x-ray beam 117 and directs the incident x-ray beam 117 to the sample 101. In some examples, x-ray optics 115 monochromes the x-ray beam incident on the sample 101. In some examples, x-ray optics 115 collimates or focuses x-ray beam 117 onto inspection region 102 of sample 101. In some embodiments, x-ray optics 115 includes one or more x-ray collimating mirrors, x-optical apertures, x-ray monochromators, and x-ray beams, or any combination thereof.

The x-ray detector 116 collects x-ray radiation 125 scattered from the sample 101 and produces an output signal 126 indicative of the nature of the sample 101 that is sensitive to incident x-ray radiation. The scattered x-rays 125 are collected by the x-ray detector 116 as the sample positioning system 140 positions and orients the sample 101 to produce an angularly resolved scattered x-ray. The x-ray detector 116 is capable of interpreting one or more x-ray photon energies and generating a signal indicative of the nature of the sample for each x-ray energy component. In some embodiments, the x-ray detector 116 includes a CCD array, a microchannel plate, a photodiode array, a microstrip scale counter, an aeration ratio counter, and a scintillator.

By way of non-limiting example, the small angle x-ray scattering meter illustrated in Figure 1 is configured as a transmission small angle x-ray scatterometer. However, in some other embodiments, the combination metrology tool 100 includes a grazing incidence small angle x-ray scatterometer.

In some embodiments, the x-ray detector is maintained in the same atmospheric environment (eg, a gas purge environment) as sample 101. However, in some embodiments, the distance between sample 101 and x-ray detector 116 is very long (eg, greater than 1 meter). In such embodiments, environmental disturbances (e.g., air turbulence) cause noise to the detected signal. Thus, in some embodiments, the x-ray detector is maintained in a partial vacuum environment separated from the sample (eg, sample 101) by a vacuum window. FIG. 3 is a diagram illustrating one of the vacuum chambers 160 containing one of the x-ray detectors 116. In a preferred embodiment, vacuum chamber 160 contains a substantial portion of the path between sample 101 and x-ray detector 116. One of the openings of the vacuum chamber 160 is covered by a vacuum window 161. The vacuum window 161 can be constructed from any suitable material (e.g., helium) that is substantially transparent to x-ray radiation. The scattered x-ray radiation 125 travels through the vacuum window 161, enters the vacuum chamber 160, and is incident on the x-ray detector 116. A suitable vacuum environment 162 is maintained within vacuum chamber 160 to minimize interference with scattered x-ray radiation 125.

The combination metrology tool 100 also includes an optical illumination system 120 and an optical detector 123. Optical illumination system 120 includes an optical illumination source 121 and optical illumination optics 122 configured to shape incident optical illumination beam 127 from optical illumination source 121 and to incident optical illumination beam 127 and incident x The light beam 117 is simultaneously directed to the inspection region 102 of the sample 101. Furthermore, the incident optical illumination beam 127 and the incident x-ray illumination beam 117 spatially overlap at the inspection region 102 of the sample 101.

By way of non-limiting example, optical illumination source 121 includes one or more arc lamps, lasers, light emitting diodes, laser driven plasma sources, and laser driven supercontinuum sources, or any combination thereof. In general, any suitable source of optical illumination can be contemplated. In some embodiments, optical illumination source 121 is configured to produce illumination light having a wavelength component between 120 nanometers and 2000 nanometers.

Illumination optics 122 are configured to collimate or focus incident optical illumination beam 127 to inspection region 102 of sample 101. In some examples, illumination optics 122 is configured to monochromize incident optical illumination beam 127. In some embodiments, illumination optics 122 includes one or more optical mirrors, focus or out-of-focus optics, optical wave plates, optical apertures, optical monochromators, and beam trains, or any combination thereof.

Optical detector 123 collects optical radiation 128 scattered from sample 101 and produces an output signal 124 indicative of the nature of sample 101 that is sensitive to incident optical radiation. The scattered optical radiation 128 is collected by the optical detector 123 as the sample positioning system 140 positions and orients the sample 101 to produce angularly resolved scattered optical radiation. The optical detector 123 is capable of interpreting one or more optical photon energies and generating a signal indicative of the nature of the sample for each optical energy component. In some embodiments, the optical detector 123 is any one of a CCD array, a photodiode array, a CMOS detector, and a photomultiplier tube.

Optical illumination system 120 and optical detector 123 can be configured in any number of known configurations. By way of non-limiting example, optical illumination system 120 and detector 123 can be configured as a spectral ellipsometer (including Mueller matrix ellipsometry), a spectral reflectometer, a spectral scatterometer, and a A stack scatterometer, a corner resolved beam profile reflectometer, a polarization resolved beam profile reflectometer, a beam profile ellipsometer, any single or multiple wavelength ellipsometers, or any combination thereof.

The combination metering tool 100 also includes a computing system 130 for acquiring signals 124 and 126 generated by the optical detector 123 and the x-ray detector 116, respectively, and determining the nature of the sample based at least in part on the acquired signal. . As illustrated in FIG. 1, computing system 130 is communicatively coupled to optical detector 123 and x-ray detector 116. In one aspect, computing system 130 receives measurement data 124 associated with simultaneous critical dimension measurements of sample 101 performed by one of x-ray beam 117 and an optical illumination beam 127. And 126.

In one example, optical detector 123 is an optical spectrometer and measurement data 124 Included is an indication of a measured spectral response to a sample based on one or more sampling procedures performed by an optical spectrometer. Similarly, in one example, the x-ray detector 116 is an x-ray spectrometer, and the measurement data 126 includes one of the measured spectral responses to the sample based on one or more sampling procedures performed by the x-ray spectrometer. Instructions.

In a further embodiment, computing system 130 is configured to access the model parameters using Instant Critical Dimensioning (RTCD), or it can access a library of pre-computed models to determine at least one sample associated with the sample 101 One of the parameter values. In general, some form of CD engine can be used to evaluate the difference between the assigned CD parameters of a sample and the CD parameters associated with the measured sample. Illustrative methods and systems for calculating sample parameter values are described in U.S. Patent No. 7,826,071, issued toK.

In a further aspect, the combination metrology tool 100 includes a computing system (e.g., computing system 130) configured to implement beam steering functionality as described herein. In the embodiment depicted in FIG. 1, computing system 130 is configured as a beam controller operative to control the positioning and spot size of incident x-ray beam 117 and incident optical illumination beam 127 such that it At any point in time, it is spatially overlapped at the desired inspection area 102 of the sample 101.

As illustrated in FIG. 1, computing system 130 is communicatively coupled to x-ray detector 116 and optical detector 123. Computing system 130 is configured to receive measurement data 124 from optical detector 123 and to receive measurement data 126 from x-ray detector 116. In one example, the measurement data 124 includes an indication of the measured optical response of the sample. Based on the distribution of the measured optical response on the surface of the detector 123, the beam controller 130 determines the incident position and area of the optical illumination beam 127 on the sample 101. In one example, pattern recognition techniques are applied by computing system 130 to determine an incident location and region of optical illumination beam 127 on sample 101 based on measurement data 124. Similarly, the measurement data 126 includes an indication of the measured x-ray response of the sample. Based on the measured x-ray response on the surface of the detector 116, by means of light The beam controller 130 determines the position and area of the x-ray beam 117 incident on the sample 101. In one example, pattern recognition techniques are applied by computing system 130 to determine the location and region of incident x-ray beam 117 on sample 101 based on measurement data 124. In response, computing system 130 generates a command signal 137 that is communicated to illumination optics 122 to redirect and reshape incident optical illumination beam 127 such that incident optical illumination beam 127 and incident x-ray beam 117 are in space. The upper portion is overlapped at the desired inspection region 102 of the sample 101. Similarly, beam controller 130 generates a command signal 136 that is communicated to either electronic optics 114 and x-optical optics 115 to redirect and reshape incident x-ray beam 117 such that incident x The light beam 117 spatially overlaps the incident optical illumination beam 127 at the desired inspection region 102 of the sample 101.

In another aspect, SAXS and optical scatter measurements are performed simultaneously on a particular test area in a number of different out-of-plane orientations. This increases the accuracy and accuracy of the measurement parameters and reduces the correlation between the parameters by extending the number and diversity of data sets available for analysis to include a variety of large angle out-of-plane orientations. Measuring sample parameters using a deeper and more diverse data set also reduces correlation between parameters and improves measurement accuracy.

As illustrated in Figure 1, the combination metrology tool 100 includes a sample positioning system configured to align the sample 101 with respect to an optical scatterometer and a small angle x-ray scatterometer over a wide range of out-of-plane angular orientations and orient the sample 101. 140. In other words, the sample positioning system 140 is configured to rotate the sample 101 about one or more axes of rotation in a plane aligned with the surface of the sample 101 over a wide range of angles. In some embodiments, the sample positioning system 140 is configured to rotate the sample 101 about one or more axes of rotation in a plane aligned with the surface of the sample 101 over a range of at least 90 degrees. In some embodiments, the sample positioning system 140 is configured to rotate the sample 101 about one or more axes of rotation in a plane aligned with the surface of the sample 101 in a range of at least 60 degrees. In some other embodiments, the sample positioning system is configured to rotate the sample 101 about one or more axes of rotation in a plane aligned with the surface of the sample 101 in a range of at least one degree. In this way, by metering system 100 An angular resolution measurement of sample 101 is collected at any number of locations on the surface of article 101. In one example, computing system 130 communicates a command signal indicative of the desired location of sample 101 to motion controller 145 of sample positioning system 140. In response, motion controller 145 generates command signals to the various actuators of sample positioning system 140 to achieve the desired positioning of sample 101.

By way of non-limiting example, as illustrated in FIG. 1, sample positioning system 140 includes an edge clamping chuck 141 to fixedly attach sample 101 to sample positioning system 140. A rotary actuator 142 is configured to rotate the edge clamp chuck 141 and the attached sample 101 relative to a perimeter frame 143. In the depicted embodiment, the rotary actuator 142 is configured to rotate the sample 101 about the x-axis of the coordinate system 146 illustrated in FIG. As depicted in Figure 1, the sample 101 is rotated in-plane about one of the rotation train samples 101 of the z-axis. The out-of-plane rotation of the rotation train sample 101 about the x-axis and the y-axis (not shown) effectively tilts the surface of the sample relative to the metering elements of the metering system 100. Although a second rotary actuator is not illustrated, the second rotary actuator is configured to rotate the sample 101 about the y-axis. A linear actuator 144 is configured to translate the perimeter frame 143 in the x direction. Another linear actuator (not shown) is configured to translate the perimeter frame 143 in the y-direction. In this manner, each location on the surface of the sample 101 can be measured over a range of out-of-plane angular positions. For example, in one embodiment, one of the samples 101 can be measured in several angular increments in a range from -45 degrees to +45 degrees relative to the vertical orientation of the sample 101.

A typical optical scatterometry system does not employ a sample positioning system that is capable of orienting a sample over a wide range of out-of-plane angular positions (eg, greater than +/- 1 degree). Therefore, the measurement information collected by such systems typically lacks sensitivity to certain parameters or cannot be used to reduce the correlation between parameters. However, the large out-of-plane angular positioning capability of the sample positioning system 140 expands the measurement sensitivity and reduces the correlation between parameters. For example, in a vertical orientation, the SAXS can resolve the critical dimension of a feature, but is substantially insensitive to the sidewall angle and height of a feature. However, by collecting measurement data over a wide range of out-of-plane angular positions, the sidewall angle and height of a feature can be resolved.

In yet another aspect, the parameters of the combined SAXS and optical scatterometry techniques can be improved by identifying common model parameters that are mathematically sequenced or parallel analyzed using a data set derived from SAXS and optical scatterometry. Accuracy and accuracy. Using a variety of metrology techniques to measure the shared parameters reduces the correlation between the parameters and improves the measurement accuracy.

In general, the SAXS and optical scatterometry techniques discussed herein measure some of the physical properties of the test sample. In most cases, the measured value cannot be used to directly determine the physical properties of the sample. The nominal measurement procedure consists of parameterization of the structure (eg, film thickness, critical dimension, etc.) and parameterization of the machine (eg, wavelength, angle of incidence, angle of polarization, etc.). Create a model that attempts to predict the measured value. The model contains the parameters associated with the _machine (P _machine ) and the parameters associated with the sample (P _specimen ).

Machine parameters are used to characterize the parameters of the metrology tool itself. Exemplary machine parameters comprise angle of incidence (the AOI), the angle of the analyzer (A _0), the angle polarizer (P _0), illumination wavelength, numerical aperture (NA) and the like. The sample parameters are used to characterize the parameters of the sample. For a film sample, exemplary sample parameters include refractive index, dielectric function tensor, nominal layer thickness of all layers, layer sequence, and the like. For measurement purposes, the machine parameters are considered to be known fixed parameters and the sample parameters are considered to be unknown floating parameters. The floating parameters are resolved by a fitting program (eg, regression, library matching, etc.) that produces a best fit between the theoretical predictions and the experimental data. The unknown sample parameter P _{specimen is} changed and the model output value is calculated until it is determined that one of the sample output values and the experimental measurement value approximately matches one of the sample parameter value sets.

In another further aspect, the combination metrology tool 100 includes a computing system configured to: generate a geometric model of a measurement structure of a sample; from the geometric model generation, each comprising at least one common geometric parameter An optical response model and an x-ray response model; and performing a fitting analysis on the x-ray measurement data by using the x-ray response model and performing a fitting analysis on the optical measurement data using the optical response model At least one sample parameter value. In the embodiment depicted in FIG. 1, computing system 130 is configured to be configured to A model building and analysis engine for model building and analysis functionality is implemented as described herein.

2 is a diagram illustrating one of an exemplary model building and analysis engine 150 implemented by computing system 130. As depicted in FIG. 2, the model building and analysis engine 150 includes a geometric model building module 151 that produces one of the geometric structures 152 of one of the measurement structures. In some embodiments, the geometric model 152 also includes the material properties of the sample. The geometric model 152 is received as an input to the x-ray response function creation module 153 and the optical response function creation module 154. The x-ray response function creation module 153 generates an x-ray response function model 155 based at least in part on the geometric model 152. In some examples, the x-ray response function model 155 is based on an x-ray appearance size

Wherein F is the apparent size, q is the scattering vector, and ρ(r) is the electron density of the sample in the spherical coordinates. Then the x-ray scattering intensity is given by the following equation

Similarly, optical response function building module 154 generates an optical response function model 156 based at least in part on the geometric model 152. In some examples, optical response function model 156 is based on Solving Maxwell's equation to predict optical scattering rigorous coupled wave analysis (RCWA) from a sample model.

The x-ray response function model 155 and the optical response function model 156 are received as inputs to the fitting analysis module 157. The fitting analysis module 157 compares the modeled x-rays and optical scatter with corresponding measurements to determine the geometry and material properties of the sample.

In some instances, modeled data is fitted to the experimental data by minimizing a chi-square value. For example, for optical metrology, a chi-square value can be defined as:

among them The optical signal 124 is measured experimentally in "channel" i, where index i describes a set of system parameters, such as wavelength, angular coordinates, polarized light, and the like. (u ₁ ,...,u _M ) is a modeled optical signal of "channel" i evaluated for a set of structure (target) parameters u ₁ , ..., u _M , where the parameters describe the geometry (film thickness, CD, sidewall angle, stack, etc.) and materials (refractive index, absorption coefficient, dispersion model parameters) and so on. σ _opt,i is the uncertainty associated with "channel" i. N _opt is the total number of channels in optical metrology. The number of parameters of the M-system characterization target. An exemplary method and system for model-based analysis of optical spectrometric data is described in U.S. Patent No. 7,478,019, issued toK. This article.

Similarly, for x-ray measurements (for example, for CD-SAXS), a chi-square value can be defined as

among them The x-ray signal 126 is measured in "channel" j, where index j describes a set of system parameters, such as energy, angular coordinates, and the like. (v ₁ , . . . , v _L ) is a modeled x-ray signal S _j of “channels” j evaluated for a set of structure (target) parameter sets v ₁ , . . . , v _L , where the parameters describe the geometry ( Film thickness, CD, sidewall angle, stack, etc.) and materials (electron density, etc.). σ _xray,j is the uncertainty associated with the jth channel. The total number of channels in the x _xray x-ray metering. The number of parameters of the L-system characteristic measurement target.

Equations (3) and (4) assume that the uncertainty associated with different channels is not relevant. In instances where the uncertainty associated with the different channels is relevant, the covariance between the uncertainties can be calculated. In these examples, one of the chi-square values for optical measurements can be expressed as

Where V _opt is the covariance matrix of the uncertainty of the optical channel, and T represents the transpose. One of the chi-square values for x-ray measurement can be calculated in the same manner.

In general, the set of target parameters for the optical model (ie, {u ₁ , . . . , u _M }) and the set of target parameters for the x-ray model (ie, {v ₁ , . . . , v _L }) is not the same. The reason is that the difference between the material constants and functions required to describe the optical and x-ray interactive program produces different target parameters. However, at least one geometric parameter is shared between the x-ray response function model 155 and the optical response function model 156. The common parameters are the same or are related to each other by a definite algebraic transformation. In some examples, target parameters such as film thickness, CD, overlay, and the like are shared between the x-ray response function model 155 and the optical response function model 156.

In some examples, the fit analysis module 157 performs a fit analysis on the x-ray measurement data 126 by using the x-ray response model 155 in sequence and performs a fit on the optical measurement data 124 using the optical response model 156. Analyze to resolve at least one sample parameter value. In some instances, first optimize And at Any parsed common sample parameter values are considered constant in subsequent optimization. Similarly, in some other examples, first optimization And at Any parsed common sample parameter values are considered constant in subsequent optimization.

In some other examples, the fit analysis module 157 parses at least the x-ray measurement data 126 using the x-ray response model 155 and performs a parallel fit analysis on the optical measurement data 124 using the optical response model 156. A sample parameter value. For example, one of the chi-square functions for parallel analysis can be defined as

Where w _opt and w _xray are assigned weighting coefficients for optical and x-ray metrology. In the simplest case, w _opt =w _xray =1. However; assigning different weights usually enhances more relevant measures. The selection of appropriate weights is usually done by experimental data analysis of reference measurements and/or for special pre-programmed experimental design (DOE) target measurement DOE parameter changes.

Optical metrology and x-ray metrology may contain more than one respective technique when calculating the chi-square value. For example, a combination of weighting coefficients assigned to each technology for grazing incidence SAXS and transmission SAXS can be used. . Similarly, a combination of weighting coefficients assigned to each technique for spectral ellipsometry, beam profile reflectance measurements, and spectral reflectance measurements can be used. .

As described above, the fit of the x-ray and optical data is achieved by minimizing the chi-square value. However, in general, the fitting of x-rays and optical data can be achieved by other functions.

The combination of optical metrology data and x-ray metrology data is useful for providing any type of x-ray and optical technology that provides complementary sensitivity to the geometric parameters and/or material parameters of interest. This is especially the case when at least one geometric parameter is shared between the x-ray model and the optical model. Sample parameters can be deterministic (eg, film thickness, CD, SWA, etc.) or statistical (eg, rms height and roughness of sidewall roughness) using a suitable model that describes interaction with the x-ray and optical beam of the sample. Related length, etc.).

The model building and analysis engine 150 improves the accuracy of the measurement parameters by any combination of feed sideways analysis, forward feed analysis, and parallel analysis. Lateral feed analysis refers to taking multiple data sets for different regions of the same sample and passing the common parameters from the first data set decision to the second data set for analysis. Forward feed analysis refers to taking a data set for different samples and forwarding common parameters forward using a stepwise replicated exact parameter forward feed route for subsequent analysis. Parallel analysis refers to applying a non-linear fit methodology to multiple data sets in parallel or simultaneously, wherein at least one common parameter is coupled during the fitting.

Multiple tool and structural analysis refers to regression-based, one-query table (ie, "library" matching) One of the other fitting programs of the plurality of data sets, forward feed analysis, lateral feed analysis, or parallel analysis. Illustrative methods and systems for multiple tool and structural analysis are described in U.S. Patent No. 7,478,019, issued toK.

It will be appreciated that the various steps described throughout this disclosure may be implemented by a single computer system 130 or alternatively by multiple computer systems 130. Moreover, different subsystems of the system 100, such as the sample positioning system 140, can include a computer system suitable for practicing at least a portion of the steps described herein. Therefore, the foregoing descriptions are not to be construed as limiting the invention. Further, the one or more computing systems 130 can be configured to perform any of the other steps(s) of any of the method embodiments described herein.

Moreover, computer system 130 can be communicatively coupled to optical detector 123, x-ray detector 116, optical illumination optics 122, and x-ray illumination optics 115 in any manner well known in the art. For example, the one or more computing computers 130 can be coupled to a computing system associated with the optical detector 123, the x-ray detector 116, the optical illumination optics 122, and the x-ray illumination optics 115, respectively. In another example, the optical detector 123, the x-ray detector 116, the optical illumination optics 122, and the x-ray illumination optics 115 can be directly controlled by a single computer system coupled to the computer system 130. Either.

The computer system 130 of the combined metering system 100 can be configured to transmit media from a subsystem (eg, optical detector 123, x-ray detector 116, etc.) by one of a wired portion and/or a wireless portion. Optical illumination optics 122 and x-ray illumination optics 115, etc., receive and/or retrieve data or information. In this manner, the transmission medium can be used as a data link between the computer system 130 and other subsystems of the system 100.

The computer system 130 of the combined metering system 100 can be configured to receive and/or retrieve data or information from other systems via a transmission medium that can include one of a wired portion and/or a wireless portion (eg, measurement results, modeled inputs) , modeling results, etc.). In this manner, the transmission medium can be used as the computer system 130 and other systems (eg, on-board memory metrology A data link between system 100, external memory or external system. For example, the computing system 130 can be configured to receive measurement data (eg, signals 124 and 126) from a storage medium (ie, memory 132 or memory 180) via a data link. For example, spectral results obtained using a spectrometer of either of the x-ray detector 116 and the optical detector 123 can be stored in a permanent or semi-permanent memory device (eg, memory 132 or 180). In this regard, spectral results can be imported from the on-board memory or an external memory system. Additionally, the computer system 116 can transmit data to other systems via a transmission medium. For example, sample parameter values 170 as determined by computer system 130 may be stored in a permanent or semi-permanent memory device (e.g., memory 180). In this regard, the measurement results can be remitted to another system.

Computing system 130 can include, but is not limited to, a personal computer system, a host computer system, a workstation, an imaging computer, a parallel processor, or any other device well known in the art. In general, the term "computing system" is broadly defined to encompass any device having one or more processors that execute instructions from a memory medium.

Program instructions 134, such as the methods described herein, may be implemented via a transmission medium transport such as a wire, cable, or wireless transmission link. For example, as illustrated in FIG. 1, program instructions stored in memory 132 are transmitted to processor 131 via bus 133. The program instructions 134 are stored in a computer readable medium (e.g., memory 132). Exemplary computer readable media include read only memory, a random access memory, a magnetic or optical disk, or a magnetic tape.

In some embodiments, a combined x-ray and optical analysis system as described herein is implemented as part of a manufacturing program tool. Examples of manufacturing process tools include, but are not limited to, lithography exposure tools, film deposition tools, implant tools, and etching tools. In this way, the result of a combined x-ray and optical analysis is used to control a manufacturing process. In one example, x-rays and optical measurements collected from one or more targets are sent to a manufacturing program tool. The x-ray and optical measurements are analyzed as described herein and the results are used to adjust the operation of the manufacturing process tool.

FIG. 4 illustrates one method 200 suitable for implementation by the combined metering system 100 of the present invention. In one aspect, it will be appreciated that the data processing block of method 200 can be implemented via one of the pre-programmed algorithms executed by one or more processors of computing system 130. Although the following description is presented under the background of the combined metering system 100, it should be appreciated herein that the particular structural aspects of the combined metering system 100 are not meant to be limiting and should be construed as merely illustrative.

In block 201, a sample is illuminated simultaneously by an x-ray illumination beam and an optical illumination beam such that the x-ray illumination beam and the optical illumination beam spatially overlap at a region to be examined on one of the surfaces of the sample.

In block 202, an amount of optical radiation from the sample is detected in response to an optical illumination beam incident on the sample.

In block 203, the amount of x-ray radiation from the sample is detected in response to the x-ray illumination beam incident on the sample.

In block 204, a first output signal indicative of one of the properties of the sample is generated. The first output signal is generated in response to the detected amount of optical radiation.

In block 205, a second output signal indicative of one of the properties of the same sample as in block 204 is generated. The output signal is generated in response to the detected amount of x-ray radiation.

FIG. 5 illustrates one method 300 suitable for implementation by the combined metering system 100 of the present invention. In one aspect, it should be appreciated that the data processing block of method 300 can be implemented via one of the pre-programmed algorithms executed by one or more processors of computing system 130. Although the following description is presented under the background of the combined metering system 100, it should be appreciated herein that the particular structural aspects of the combined metering system 100 are not meant to be limiting and should be construed as merely illustrative.

In block 301, a geometric model of one of the structures of one of the samples is generated. Illuminating the structure by an x-ray illumination beam and an optical illumination beam, wherein the x-ray illumination beam and the optical illumination beam are spatially overlapped on one of the surfaces of the sample to be inspected. At the office.

In block 302, an optical response model and an x-ray response model are generated based at least in part on the geometric model. Both the optical response model and the x-ray response model comprise at least one common geometric parameter from the geometric model.

In block 303, a first signal is received indicating that one of the amount of optical radiation from the sample is detected in response to the optical illumination beam.

In block 304, a second signal is received indicating that one of the x-ray radiation doses from the sample is detected in response to the x-ray illumination beam.

In block 305, at least one sample parameter value is determined based on a fit analysis of the first signal using the optical response model and a fitting analysis of the second signal using the x-ray response model.

In block 306, the sample parameter values are stored in a memory (eg, memory 132).

As described herein, the term "critical dimension" encompasses any critical dimension of a structure (eg, bottom critical dimension, intermediate critical dimension, top critical dimension, sidewall angle, grating height, etc.), any two or more structures One of the critical dimensions (eg, the distance between two structures) and one of the displacements between two or more structures (the stack-to-stack displacement between the stacked pairs of grating structures, etc.). The structure may comprise a three-dimensional structure, a patterned structure, a stacked structure, and the like.

As described herein, the terms "critical dimension application" or "critical dimension measurement application" encompass any critical dimension measurement.

As described herein, the term "metering system" encompasses any system that at least partially characterizes a sample in any aspect, including critical dimension applications and stack-to-measurement applications. However, such terminology does not limit the scope of the term "metering system" as described herein. Additionally, the metering system 100 can be configured to measure patterned wafers and/or unpatterned wafers. The metering system can be configured as an LED inspection tool, edge inspection tool, back A face inspection tool, a macro inspection tool or a multi-mode inspection tool (involving data from one or more platforms at the same time) and any other measurement or inspection tool that facilitates calibration of system parameters based on critical dimension data.

Various embodiments are described herein for a semiconductor processing system (e.g., an inspection system or a lithography system) that can be used to process a sample. The term "sample" is used herein to refer to a wafer, a reticle, or any other sample that can be processed (e.g., printed or inspected for defects) by means well known in the art.

As used herein, the term "wafer" generally refers to a substrate formed from a semiconductor or non-semiconductor material. Examples include, but are not limited to, single crystal germanium, gallium arsenide, and indium phosphide. Such substrates are typically found and/or processed in semiconductor fabrication facilities. In some cases, a wafer may only comprise a substrate (ie, a bare wafer). Alternatively, a wafer may comprise one or more layers of different materials formed on a substrate. One or more of the layers formed on a wafer may be "patterned" or "unpatterned." For example, a wafer can include a plurality of dies having repeatable pattern features.

A "folding reticle" can be used to doubling the reticle at one of the stages of the refractory manufacturing process, or may or may not be released for use in one of the semiconductor fabrication facilities to complete the doubling mask. A double refracting hood or a "mask" is generally defined as having substantially transparent substrate one of the substantially opaque regions formed thereon and configured in a pattern. The substrate may comprise, for example, a glass material such as amorphous SiO ₂ . The double reticle can be placed over a wafer covered with photoresist during one of the exposure steps of a lithography process such that the pattern on the reticle can be transferred to the photoresist.

One or more of the layers formed on a wafer may be patterned or unpatterned. For example, a wafer can include a plurality of dies each having repeatable pattern features. The formation and processing of such material layers can ultimately result in a completed device. Many different types of devices can be formed on a wafer, and the term wafer as used herein is intended to encompass a wafer on which any type of device known in the art is fabricated.

In one or more exemplary embodiments, the functions described can be implemented in any combination of hardware, software, firmware, or the like. If implemented in software, the functions may be stored on or transmitted as one or more instructions or code on a computer readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one location to another. A storage medium can be any available media that can be accessed by a general purpose or special purpose computer. By way of example and not limitation, the computer-readable medium can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage device, or can be used to carry or store instructions The required code in the form of a data structure and any other medium accessible by a general purpose or special purpose computer or a general purpose or special purpose processor. Furthermore, any connection is also suitably referred to as a computer-readable medium. For example, if the soft system uses a coaxial cable, fiber optic cable, twisted pair cable, digital subscriber line (DSL), or wireless technology such as infrared, radio, and microwave to transmit from a website, server, or other remote source, then the coaxial cable, Fiber optic cables, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of the media. As used herein, a magnetic disk and a compact disk include a compact disc (CD), a laser disc, a compact disc, a digital versatile disc (DVD), a floppy disc, and a Blu-ray disc, wherein the disc usually reproduces data magnetically and the disc uses laser optics. Reproduce the information. The above combinations should also be included in the scope of computer readable media.

Although certain specific embodiments have been described above for the purposes of the description, the teachings of this patent document have general applicability and are not limited to the specific embodiments described above. Accordingly, various modifications, adaptations, and combinations of the various features of the described embodiments can be practiced without departing from the scope of the invention as set forth in the appended claims.

100‧‧‧Combined metering system/combination metering tool

101‧‧‧ samples

102‧‧‧Inspection area

110‧‧‧x light lighting system

111‧‧‧Liquid metal container

112‧‧‧Liquid metal collector

113‧‧‧Electronic beam source

114‧‧‧Electronic optics

115‧‧‧x optical optics

116‧‧‧x photodetector

117‧‧‧x light beam

118‧‧‧Electronic flow

119‧‧‧ liquid metal jet

120‧‧‧Optical lighting system

121‧‧‧ Optical illumination source

122‧‧‧Optical illumination optics

123‧‧‧ Optical detector

124‧‧‧Signal/output signal/measurement data/measurement optical signal

125‧‧‧x optical radiation

126‧‧‧Output signal/measurement data/measurement x-ray signal

127‧‧‧ Optical illumination beam

128‧‧‧Optical radiation

130‧‧‧Computation System / Beam Controller / Computer System

131‧‧‧ processor

132‧‧‧ memory

133‧‧‧ busbar

134‧‧‧Program Instructions

136‧‧‧ command signal

137‧‧‧Command signal

140‧‧‧Sample Positioning System

141‧‧‧Edge clamp chuck

142‧‧‧Rotary actuator

143‧‧‧ Peripheral framework

144‧‧‧Linear actuator

145‧‧‧ motion controller

146‧‧‧ coordinate system

Claims (20)

A metrology tool comprising: a liquid metal based x-ray illumination system comprising a liquid metal x-ray illumination source and x-ray illumination optics configured to shape from the x-ray illumination One of the sources incidents an x-ray beam and directs the incident x-ray beam to a test region of a sample; an x-ray detector configured to receive radiation from the sample in response to the incident x-ray beam and to generate an indication a signal of a first property of the sample; an optical illumination system comprising an optical illumination source and an optical illumination optics configured to shape an incident optical illumination beam from one of the optical illumination sources and Directing the incident optical illumination beam and the incident x-ray beam to the inspection region of the sample, wherein the incident optical illumination beam and the incident x-ray beam spatially overlap at the inspection region of the sample; and an optical A detector configured to receive optical radiation from the sample in response to the incident optical illumination beam and to generate a signal indicative of a second property of the sample. The metrology tool of claim 1, further comprising: a beam controller operative to communicate a first command signal to the x-ray illumination optics system to redirect the incident x-ray beam and to a second command Transmitting a signal to the optical illumination optics system to redirect the incident optical illumination beam such that the incident optical illumination beam and the incident x-ray beam spatially overlap the inspection region of the sample, wherein the first command signal and The second command signal is determined based at least in part on the radiation received from the sample in response to the incident x-ray beam and the radiation received from the sample in response to the incident optical illumination beam. The metering tool of claim 1, which further comprises: A wafer positioning system configured to selectively position the sample with a plurality of different out-of-plane orientations of a flat surface of the sample to simultaneously illuminate the inspection region by the incident x-ray beam and the incident optical illumination beam . The metrology tool of claim 1, wherein the wafer positioning system is configured to selectively position the one or more axes of rotation in a plane that is aligned with the surface of the sample in at least one degree sample. The metrology tool of claim 1, further comprising: a model building and analysis engine configured to: generate a geometric model of one of the structures of the sample; generate an optical response model based at least in part on the geometric model and an x a light response model, wherein the optical response model and the x-ray response model both contain at least one common geometric parameter from the geometric model; receiving the signals generated by the x-ray detector to obtain an x-ray quantity Measuring a data set; receiving the signals generated by the optical detector to obtain an optical measurement data set; and fitting and analyzing the x-ray measurement data set based on using the x-ray response model The optical response model determines at least one sample parameter by fitting analysis of one of the optical measurement data; and storing the at least one sample parameter value. The metrology tool of claim 5, wherein the value of the at least one common geometric parameter is determined based on the fitting analysis of the x-ray measurement data set, and in the fitting analysis of the optical measurement data set This decision value is treated as a constant. The metrology tool of claim 5, wherein the at least one common geometric parameter is included in one of the fitting analysis of the x-ray measurement data set and the fitting analysis of the optical measurement data set Considered as a global parameter. The metering tool of claim 1, wherein the liquid metal based x-ray illumination system, the x-ray illumination optics system, and the x-ray detector are configured to transmit a small angle x-ray scattering system and a small grazing incidence Any of the angle x light scattering systems. The metrology tool of claim 1, wherein the x-ray detector is located in a partial vacuum environment separated from the sample by a vacuum window. The metrology tool of claim 1, wherein the first property and the second property of the sample are of the same nature. The metering tool of claim 1, wherein the liquid metal x-ray illumination source comprises: a liquid metal source for heating and melting at least one metal and generating a liquid metal jet, a liquid metal collector for obtaining the a liquid metal jet stream, a liquid metal circulation system for returning liquid metal from the liquid metal collector to the liquid metal source, and an electron beam source for directing an electron beam to the liquid metal jet stream, Thereby, the incident x-ray beam that can be directed towards the inspection region is generated. A method comprising: simultaneously illuminating a sample with an x-ray illumination beam and an optical illumination beam such that the x-ray illumination beam and the optical illumination beam spatially overlap one of the areas of the sample to be examined Responding to the amount of optical radiation from the sample in response to the optical illumination beam incident on the sample; detecting the amount of x-ray radiation from the sample in response to the x-ray illumination beam incident on the sample; Generating, at the detected amount of optical radiation, a first signal indicative of one of the first properties of the sample; and generating a second property indicative of one of the samples in response to the detected amount of x-ray radiation A second signal. The method of claim 12, further comprising: redirecting the optical illumination beam based on the first signal such that the optical illumination beam is incident on the surface of the sample at the desired region; and redirecting based on the second signal The x-ray illumination beam is such that the x-ray illumination beam is incident on the surface of the sample at the region to be inspected. The method of claim 12, further comprising: rotating the sample to a plurality of different out-of-plane orientations of the surface of the sample. The method of claim 12, further comprising: generating a geometric model of one of the structures of the sample; generating an optical response model and an x-ray response model based at least in part on the geometric model, wherein the optical response model and the x-ray response The model includes at least one common geometric parameter from the geometric model; receiving the first signal and the second signal; fitting and analyzing the first signal based on using the optical response model and using the x-ray response model Determining at least one sample parameter value by fitting analysis to one of the second signals; and storing the at least one sample parameter value. The method of claim 15, further comprising: determining one of the at least one common geometric parameter based on the fitting analysis of the second signal, wherein the at least one common in the fitting analysis of the first signal This decision value of the geometric parameter is treated as a constant. The method of claim 15, further comprising: determining one of the at least one common geometric parameter based on using the optical response model for the first signal and using the x-ray response model to perform a parallel fit analysis on the second signal value. A non-transitory computer readable medium comprising: a code for causing a computer to generate a geometric model of a structure of a sample, wherein the structure is illuminated simultaneously by an x-ray illumination beam and an optical illumination beam An x-ray illumination beam spatially overlapping the optical illumination beam at a region to be examined on one of the surfaces of the sample; for causing the computer to generate an optical response model and an x-ray response model based at least in part on the geometric model a code, wherein the optical response model and the x-ray response model both comprise at least one common geometric parameter from the geometric model; for causing the computer to receive an indication in response to the optical illumination beam detecting an optical from the sample a code of a first signal of the amount of radiation; a code for causing the computer to receive an indication of a second signal from one of the x-rays of the sample in response to the x-ray illumination beam; for causing the computer Based on fitting the analysis of one of the first signals using the optical response model and using the x-ray response model to fit the analysis of one of the second signals a code of at least one sample parameter value; and a code for causing the computer to store the at least one sample parameter value. The non-transitory computer readable medium of claim 18, further comprising: a code for causing the computer to determine a value of the at least one common geometric parameter based on the fitting analysis of the second signal, wherein The decision value of the at least one common geometric parameter in the fitting analysis of the first signal is considered to be a constant. The non-transitory computer readable medium of claim 18, further comprising: causing the computer to fit the first signal and the one of the second signals using the optical response model in parallel using the optical response model A code for determining one of the values of the at least one common geometric parameter is analyzed.