Design of a second harmonic generation (SHG) optical inspection system.

Abstract

To overcome disadvantages when employing second harmonic generation (SHG), as established technique for semiconductor manufacture and measurement.SOLUTION: Second Harmonic Generation (SHG) can be used to interrogate a surface of a sample such as a layered semiconductor structure. The SHG based sample interrogation systems may simultaneously collect different polarization components of the SHG signal at a time to provide different types of information. SHG imaging systems 10000 can provide SHG images or maps of the distribution of SHG signals over a larger area of a sample 4120. Some such SHG imaging systems employ multiple beams and multiple detectors to capture SHG signals over an area of the sample. Some SHG imaging systems employ imaging optics 10114 to image the sample onto a detector array 10116 to form SHG image.SELECTED DRAWING: Figure 23

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application is filed May 2018 under the benefit of priority under 35 U.S.C. §119(e). U.S. Provisional Patent Application No. 62 / 671,616, filed on the 15th, entitled "Second Harmonic Generation (SHG) Imaging" "Design of an Optical Inspection System Based on a Method for Providing a High-Performance Image," and U.S. Provisional Application No. 62, filed May 15, 2018. / 671611 "System Design for Hybrid Polarized Optical Second Harmonic Generation" Incorporated by reference.

[0002] This application relates to second harmonic generation (SHG) based wafer inspection, semiconductor metrology, materials The present invention relates to a system for characterization, surface characterization and / or interface analysis. [Background technology]

[0003] In nonlinear optics, light beam inputs are converted into sum, difference, or harmonic frequencies of the inputs. Second harmonic generation (SHG) is a process in which light is generated at an angle by splitting the incident light beam into two equal parts. This is a nonlinear effect in which radiation is emitted from a material at twice the frequency of the incident radiation. Two photons of energy E combine to produce a single photon of energy 2E ( This means that light with twice the frequency (2ω) or half the wavelength is generated. do.

[0004] A survey of scientific research using SHG techniques is given by T. F. Heinz et al., "From Semiconductor Surfaces to "Optical Second-Harmonic Generation of Lasers," Advances in Laser Research III (A.C. Tam, J.L. Cole, W. C. Stewart, ed., American Physical Society, New York, 1988), p. 452 As can be seen, the SHG process is most effective in materials that exhibit a center of symmetry (i.e. In these materials, the SHG process does not occur in the bulk of the symmetric, inverted, or centrosymmetric materials. The process can only be recognized at surfaces and / or interfaces where the inversion symmetry of the bulk material is broken. Therefore, the SHG process offers unique sensitivity to surface and interface properties. do.

[0005] For a similar understanding, the SHG effect is described in U.S. Pat. No. 5,294,289 to Heinz et al. No. 5,557,409 to Downer et al., U.S. Pat. No. 67,477 to Hunt, and U.S. Pat. No. 95175, No. 6781686, No. 6788405, No. 6819844, No. 68 Nos. 82414 and 7304305, No. 6856159 of Talk et al., and No. Ares et al. Each of the 7,158,284 patents also describes other techniques or " However, the teachings of these patents do not affect the semiconductor manufacturing and Some of the major obstacles to adopting SHG as an established technique for metrology remain to be overcome. It seems so. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Patent No. 5,294,289 [Patent Document 2] U.S. Patent No. 5,557,409 [Patent Document 3] U.S. Patent No. 6,795,175 [Patent Document 4] U.S. Patent No. 6,781,686 [Patent Document 5] U.S. Patent No. 6,788,405 [Patent Document 6] U.S. Patent No. 6,819,844 [Patent Document 7] U.S. Patent No. 6,882,414 [Patent Document 8] U.S. Patent No. 7,304,305 [Patent Document 9] U.S. Patent No. 6,856,159 [Patent Document 10] U.S. Patent No. 7,158,284 [Non-patent literature]

[0007] [Non-Patent Document 1] T.F. Heinz et al., "Optical Second-Harmonic Generation from Semiconductor Surfaces," Advances in Laser Research III (edited by A.C. Tam, J.L. Cole, and W.C. Stewarley, American Physical Society, New York, 1988), p.452 Summary of the Invention

[0008] (Part I) Electrons in the semiconductor substrate layer have different power characteristics for sum frequency generation (SFG) The SHG measurement tools excited differently by each pump and probe light source are described. For such techniques, a stacked semiconductor device template is used. An "additional" integrated light source ( a short-wavelength laser (e.g., an ultraviolet flash lamp or laser) acting as a "probe" light source. Measurements are provided with pulsed or ultrashort pulsed lasers (e.g., femtosecond solid-state lasers). It provides a characterization tool for single laser SHG or dual or multiple laser Two different sources for different purposes, clearly distinguishable from the SFG system. in unison or in conjunction with each other (with various time offsets and / or variable The resulting energy comes from the use of pump energy.

[0009] One method is to reduce the total characterization time for some materials for pumps. Many such implementations use the time-dependent In one variation of this method, the electric field is not primarily generated by the probe / probe laser. The pump illuminates the entire wafer with UV light, and then the probe laser is used to probe the wafer. Rasterize the whole or part of the image while taking the minimum probe time per point. , or otherwise scan (e.g., as fast as your hardware can move the laser) Options in this regard include wafer movement along a (scan) row, Another approach involves scanning the wafer in a radial direction. You can also rotate it along the screen and scan it.

[0010] In another variation, the pump induces rapid charging at the sample location at the material interface, followed by In this case, the decay of the charging interface by a probe involving fast cutoff and / or optical delay methods The method is described in U.S. Provisional Application No. 61 / 98, filed April 17, 2014. No. 0860, "Wafer Metrology," Section II, "Systems and Methods for Measuring Charge Decay" Regardless, in various embodiments, the pre-excitation The intended use of the pump is to transport charge carriers into the dielectric in sufficient quantities to impact the interface, e.g. The key is to inject it into the

[0011] Alternatively, the pump laser can be used to generate the S already generated at the sample location by the probe laser. It can be used as a post-excitation or post-excitation light source to affect the HG signal. , SHG generated by pre-pump and post-pump laser energy application to the probe Use signal comparison / contrast to probe the sample and measure the SHG response before pumping. The pump is then measured by applying radiation from a pump source and then re-probing. The difference in SHG response before and after trapping can be used to characterize further material properties, such as trap density in dielectric materials. can be determined.

[0012] In the various methods discussed herein, timing differences (i.e., the use of a probe laser) The pump source (depending on whether it is pre-pumped and / or post-pumped) is used to measure the material interface. Survey curves can be collected that provide further information about all of the

[0013] In various methods, pump and probe sources are used simultaneously, and their combination This is used to provide an SHG signal for determining the injection carrier energy threshold. Specifically, a tunable pump laser is used while the probe laser is used to probe. At a certain frequency, the SHG signal exhibits an inflection point (or a region of discontinuity). The value corresponding to the pump laser frequency at the inflection point (or discontinuity region) is the injection capacitance. It can be related to the rear energy threshold.

[0014] Various embodiments of the subject pump and probe systems may require specific hardware In the example where the pump is a flash lamp, this is a very reasonable cost. Cost reductions can be achieved for two-laser systems. The pump and probe systems contemplated herein, whether or not a second laser is provided, The combination of the probes also reduces the risk of optical damage to the substrate being investigated. Too much irradiation, exceeding the average power threshold, can degrade the dielectric and even the substrate. The average power threshold that causes optical damage to the substrate is determined by experimental calibration studies. We can decide that.

[0015] To understand the latter possibility in relation to the target hardware, some background is provided. That is, the pump and probe energies alone can The pump and probe sources can be used to generate the SHG signal. pumps do not need to operate in tandem to generate the S Since we do not have the peak power to adequately drive HG, the relevant material properties are primarily , which is derived from the method of interest by the SHG signal intensity generated by the probe. The existing SHG intensity curves are the distribution of charge carriers across the interface, e.g., between the dielectric and the substrate. For example, the injection of carriers across the interface between the dielectric and the semiconductor substrate The time required depends on the average power directed onto the sample. The probe alone can allow injection of carriers across the interface between the dielectric and the substrate. In practical implementations, the average power cannot be separated from the peak power, which can lead to optical damage to the material. The objective is to allow injection of carriers across the interface between the dielectric and the substrate without exceeding a threshold. The time to reach the target mean power is shorter than when using a combined pump and probe implementation. A source with high average power but low peak power can be placed in the dielectric and By using it as a pump to inject carriers across the interface between the substrate and the semiconductor, the average power The time to increase the average power may be a potential hazard that high peak power can induce. Savings without damage complications.

[0016] Therefore, the target probe is typically a more sensitive probe with a lower average power than the pump. In other words, the probe laser is usually a relatively very In one aspect, this minimizes disturbance to the intrinsic electric field present at the substrate interface. This allows the generation of an initial time-independent signal.

[0017] Higher average power but lower peak power pumps can drive charge carriers to the material interface. or by jumping to the energy level across the interface, inducing an electric field (E) A relatively high average power source is used as a pump, and all available electrons are pumped at least By providing at least enough energy to jump to the dielectric, the interface is rapidly "Charging" provides high peak power (providing high SHG conversion rates) but low Probe of average power (due to short pulse duration and limited number of such pulses) This creates a situation where blazars can rapidly probe the surface and provide time-independent SHG signal data. can be.

[0018] Therefore, in various embodiments described herein, the probe laser generates electrons. The decrease in the time required to move a molecule across a higher energy level or interface This allows for faster measurement of steady-state SHG signals and / or charge carrier time dynamics. This method also allows for rapid evaluation of the effectiveness of the SHG probe. The effect of the SHG process on the electric field at the interface of the substrate can be separated. Not only can the signal from the probe beam be made faster or negligible, This allows for faster acquisition of at least some of the time-independent SHG data. From another perspective, the energy of carrier injection into an interface (e.g., an interface between a semiconductor and a dielectric) Faster and / or more accurate determination of energy thresholds, as well as in a line tool environment Whatever the situation, the short available time it provides The reduction enables high throughput testing for all types of in-line metrology tools in the semiconductor industry. As an example, a 10 nm silicon-on-insulator Devices with 25nm buried oxide layer (10nm device layer / 25nm BOX S OI) to create time-dependent curves using existing applications of SHG technology This requires 6-12 or more seconds per point. The time dependence can be generated in less than a second, and the material and pump / probe powers can be synchronized. This advancement allows for the Cover 10x more surface area on the wafer or achieve the same reliability in 10% of the time And these kinds of values ​​depend on the material, layer thickness, and specific pump / probe It varies by power and wavelength, but is enlightening.

[0019] Embodiments of the present invention include methods related to the techniques described herein, and methods for carrying out the methods. Hardware for the purpose of the provision of services, and related products (including products by process) Each of these includes a production system incorporating the above.

[0020] (Part II) To date, the adoption of SHG-based metrology tools has been limited. This fact is reflected in the existing systems. This is likely due to the system's inability to distinguish between the detected interface characteristics. Existing SHG techniques do not provide a means to determine the location and presence of interfacial electrically active anomalies. However, these methods rely on relative measurements and are not sensitive to the type of electrically active anomaly (e.g. , adsorbed contaminants such as copper for binding defects) and / or It is practically impossible to quantify the contaminant.

[0021] However, the subject systems and methods eliminate the determination necessary for such activity. These systems and methods are capable of capturing quantitative information for making decisions. In this method, a wafer sample is exposed to optical electromagnetic radiation (a pulsed laser or flash laser) at specific locations. After charging with a lamp or other electromagnetic energy source or light source or other means, Measurements are made to monitor the transient electric field decay associated with the heterogeneous interface, which controls the decay period.

[0022] Using decay curve data generated and characterized at multiple points, anomalies or Identify and / or define the defect type or contaminant for the spectroscopic parameter in question. In all cases, decay-dependent data can be collected and determined to be quantifiable. , determining charge carrier lifetime, trap energy and / or trapped charge density. By this, defects and contaminants can be distinguished from each other or analyzed, and if a contaminant is detected, provides a system capable of identifying species and / or quantifying contaminants if detected Used to:

[0023] Such activity is measured location by location in a selected manner, typically across the entire wafer or other Repeated scans of the material sample or area are performed to determine the The computation required to do this is done in "real time" (i.e., virtually no time is required to output the results). There may be delays during scanning (or post-processing). Therefore, in various embodiments, the precise method for obtaining target data, as described below, is Provides system timing so control software can run without delay.

[0024] Optionally, the charging of the sample material is monitored in relation to the generation of an SHG signal. The information obtained via this signal can be used for material analysis and determination.

[0025] In either case, the system embodiment includes: 2 Seconds to picoseconds (10 -12 seconds ) range. The system is designed to detect the surface and buried interfaces of thin film materials after introducing multiple short interruption intervals. These intervals can be used to monitor the SHG signal generation at the sample position of interest. It can be timed to monitor the field decay.

[0026] The system may also include optical line delays. Delay lines are used to provide, among other things, dispersion compensation and polarization It may be a fiber-based device when combined with light control optics; or ,Delay lines are based on mirrors, McDonald's U.S. Patent No. 6,147,799, Bishop et al. No. 6,356,377 to Wu et al., or No. 6,751,374 to Wu et al. In either case, the delay is set to a value that allows the laser to interrogate the material for picoseconds (10 -12 seconds)~ Femtoseconds (10 -15 seconds), possibly attoseconds (10 -18 seconds) Such investigations involve multiple charge decay dependent measurements along a single decay curve. It may be useful to find data points.

[0027] The subject method measures the SHG signal for decaying data points acquired after successive charging events. The condition for acquiring the SHG signal is determined by measuring the SHG signal at each charging event. Additionally, the time interval between successive charging events may vary. This method involves correlating multiple data points (at least two, usually three or more) to Alternatively, the minimum destructive (i.e. (The radiation used to generate the SHG signal does not significantly charge the material) A probe event is used after a single charging event.

[0028] Yet another method for determining transient charge decay is to measure the charge decay of the sample material (or more precisely, the charge decay of the sample material). The time dependence of this signal is measured. The dynamics can be treated in the same way as when SHG measurements are employed. As noted, such measurements may be performed over a decay interval and / or at a given level following charging. In any case, for such use Specific electrode hardware is detailed below.

[0029] Regarding charge or charge level, charge dynamics can be measured on a standard linear or logarithmic time scale. It may be an apparent saturation point when observed against the above. Depending on the situation, the charging rate is observed, recorded, and analyzed, which may yield important information.

[0030] For successive charge / probe events, the initial state of charge of the sample is measured and the saturation level is determined. If the state of charge is not far away, the system may skip further or subsequent characterization. In this situation, the case where it can be considered "not far" is when using the tool in question. The initial state of charge, determined by learning when to sample for a fixed period of time. This may mean that the charge increase relative to the surface area is about 1% to about 10%.

[0031] In other words, the so-called "saturation" is a relative term. However, the SHG signal intensity related to the charge When observed on a logarithmic scale of 10 to 100 seconds, the latter part of the saturation occurs with a different time constant. It can be observed that the reaction is relatively slower or takes longer. Although the methodology examples discussed here discuss charging to saturation, delays and other timing considerations may also be considered. The degradation can be seen as occurring in terms of apparent saturation, which takes an unnecessarily long time to reach. Rather than waiting the full amount of time for 100% saturation, the device Regardless of the time it takes to reach apparent saturation or extract a significant parameter, It may be delayed until it can be released.

[0032] Also, monitor the amount or extent of charge going towards saturation (e.g., in connection with SHG monitoring). In this case, the subject method and system may be able to generate meaningful decay curve information while avoiding saturation. It is understood that the device can operate at charge and / or recharge levels below (as explained above). However, when such measurements are not possible and the approximate saturation is a known parameter, (e.g., by exposing the target tool to a given material) to a saturated charge as the target level. Use it.

[0033] It also aids in the analysis of materials by introducing a DC bias across the sample being tested. Using a DC bias, the initial charge at the interface is reduced before the photoinduced voltage can take effect. To do this, the sample to be tested is placed on the sample surface using a probe. A conductive chuck that can be used as a ground to apply a DC bias across the sample. Furthermore, similar induction can be achieved without the use of a surface probe. Other means of introducing a voltage bias are described in U.S. Provisional Application No. 6, filed April 17, 2014. Section IV "Electric Field Bias SHG Technology" in the specification of No. 1 / 980860, "Wafer Measurement Technology" It is described in detail.

[0034] The system also includes a primary laser in the cutoff analysis for determining charge decay. A set of such light sources may be used. Section I of the specification of U.S. Provisional Application No. 61 / 980860, "Wafer Metrology Techniques," "Pumps and Pumps" As detailed in "Lobe-type SHG Measurements," the device is used as a radiation pump / probe combination. There is a possibility that it will be used.

[0035] All embodiments of the present invention are intended to be illustrative and not restrictive of the principles of the present invention. The components or features, methods, and Hardware for the execution of the process, the hardware and the product (product by process) This includes in combination with a production system incorporating

[0036] (Part III) Various bias fields (e.g., magnetic field bias, DC bias, and / or capacitive coupling) and / or a voltage bias induced by an AC field alone, accompanied by a changing magnetic field. We will cover these in turn. They can be used independently and / or in combined systems. Various embodiments described herein relate to methods related to the above techniques, methods The hardware that runs it, the hardware and the product (including the product by process) This includes production systems that incorporate

[0037] (magnetic field bias) When a static or changing magnetic field is applied to a sample, the change in the second-order optical susceptibility tensor of the material Therefore, a magnetic field can be used to optimize the SHG signal from the sample. Additionally, as explained further below, a varying magnetic field can be used to This can induce bias.

[0038] (Induced voltage bias to eliminate DC contact probes) A system and method for characterizing the SHG response of layered semiconductor materials is described. The material is then subjected to a ion beam across its entire interface without the use of a contact bias probe in the system. and the electric field is induced by a pulse of a probe laser and / or a detector. The opening and closing of the switch is synchronized with a variable or pulsed AC bias of a predetermined amplitude applied to the sample. An induced voltage field can be generated that corresponds to or is aligned with the surface to be probed.

[0039] The target hardware is an SHG device (e.g., U.S. Provisional Application No. Section II of the specification of No. 61 / 980860, "Wafer Measurement Technology," "System and Method for Measuring Charge Decay and methods) is applied to or along the surface of the device without contact. together with means for directing (e.g., components configured to direct) such means. The step or part is contacted either by backside contact with a probe or via a conductive chuck. and a capacitance connected to a power source that also communicates with the backside contact probe or such chuck. Alternatively, the sample may be coupled with a probe for the purpose of inducing an external voltage field at its multilayer interface. By applying a magnetic field that varies with

[0040] A variable waveform (AC if necessary) power supply generates a transient electric field (as opposed to any of the above techniques) Through the application of the voltage and the material interface electric field, The relationship can be modeled as a transfer function or in other ways. This includes various (capacitive) This includes taking into account external influences (e.g., eigenvalues, eigenvalues, or other). By applying an AC (or other) current of amplitude and frequency, the electric field amplitude value at the interface is approximately For SHG characterization of test points that are almost instantaneously constant, a laser shutter and / or It may be used as a timing cue to simultaneously trigger photon counters. The system then applies a voltage to the top surface (i.e., the device layer of the substrate) via a contact electrical probe. It is possible to simulate a constant (DC) voltage that

[0041] Applying AC directly to the backside of the specimen causes the system to operate like a "neutral" or grounded chuck. , and the bulk and device layers at equilibrium potential. Then, the bulk or multilayer semiconductor material An AC bias is applied to the chuck, which is in galvanic contact with the substrate layer. It is separated from the bulk by an oxide layer and does not directly connect to a conductor, so it is A potential field or voltage is created (i.e., induced) between the bulk layers.

[0042] Alternatively, it is located in the vicinity (within about 1 to 2 mm) of the upper surface of the sample without contacting it. Capacitively coupled probes may be used. The preferred approach in this regard is to measure the entire wafer. A plate large enough to cover (but not touch) the body, and the plate is A small hole is formed through which the SHG beam passes toward the sample and through which the SHG beam exiting from the sample passes. It may have holes and be hovering in the air.

[0043] In some implementations, the contactless electrodes can be realized using MEMS technology. For example, in one implementation, a Si wafer can be oxidized on both sides. Then, a spiral or A grid of electrodes is deposited on one or more locations on the wafer. Oxide material can be removed from the backside of the wafer at these locations. In such an implementation, an electromagnetic field applied to the electrodes couples the wafer via near-field inductive coupling. It can be inductively biased, using a magnetic field generated by an external current to control deposition. By inducing a current through the electrodes, a current can be generated across the wafer. Other methods of implementing the contact probe may also be used.

[0044] In either case, SHG techniques are used to investigate the sample, e.g., 201 The specification of U.S. Provisional Application No. 61 / 980,860, filed April 17, 2004, entitled "Wafer Measurement Technology" The details are given in Section I, "Pump and Probe SHG Measurements." This is also true for the other embodiments discussed.

[0045] Regardless, in the subject embodiment, SHG is monitored as a function of voltage across the interface. Since it is desirable to synchronize the SHG signal with the power source, this synchronization is Laser, laser alone, or SHG signal used for generation and SHG signal processing software This can be achieved by controlling the signal processing software only in time with the voltage change. The voltage of the chuck can also be controlled.

[0046] The advantage of this synchronization is that SHG measurements with voltage bias are similar to SHG measurements with DC bias. can be obtained without using contact voltage bias probes on the surface of the wafer. Instead of applying a DC bias, the system synchronizes the SHG measurement and / or generation. A controlled AC bias is used to collect SHG data at different points in the voltage cycle. The bias can be applied using near-field inductive coupling or via capacitive coupling to the sample. The SHG data collected with these biasing techniques exhibit the same material properties as DC-biased SHG. Generate information.

[0047] Reduce or minimize noise and obtain statistically relevant metrics as a function of voltage across the interface. To obtain a .

[0048] (Induced voltage bias for characterizing interfacial leakage) Interfacial leakage current and / or carrier injection energy between layers of stacked (e.g., semiconductor) materials Regarding energy, SHG and the voltage change (e.g. , alternating, variable and / or pulsed voltage or current signals, or within the device layer of the sample. A system for characterizing a device that uses a magnetic field to induce a voltage change in the device and This section explains how to call it.

[0049] Applying an alternating current, variable and / or pulsed voltage to the stacked semiconductor / dielectric structure While or immediately after application, a pulsed laser is directed at the layered semiconductor material. By measuring the SHG response from the generated optical pulse, the interface leakage current and In some embodiments, the carrier injection energy and / or carrier density can be characterized. By measuring the time evolution of the SHG signal from the interface as a function of the decay time constant of the induced voltage, This provides information about the mobility of charge carriers across the interface.

[0050] (Induced voltage bias for characterizing carrier injection energy threshold) The energy threshold for photoinduced charge carrier injection into the dielectric in layered semiconductor materials is Instead of using tunable laser excitation, a method related to a varying electric field in the device layer of the sample is used to determine This paper describes a system and method for SHG measurement using a dielectric material. To measure the energy threshold required for photoinduced charge carrier injection, the aforementioned materials were The layered semiconductor is then exposed to a substantially monochromatic incident photon beam to generate SHG. The voltage across the material interface is incrementally changed until the SHG response shows a large bend or discontinuity. The SHG signal increases with each incremental voltage change until the SHG signal shows a sudden change in slope from the previous measurement. The change in gradient can be measured as a maximum or minimum (e.g., a maximum or minimum). It could be a minimum, a cusp, or a step function. The transfer of net charge change due to the electrons is based on the third harmonic injection current, the forward current to the dielectric due to the strong electric field. It can be explained as the integral of the contributions of the "direction" leakage current and the "reverse" discharge leakage current. In formula form, it is as follows:

number

[0051] All embodiments of the present invention are intended to be illustrative and not restrictive of the principles of the present invention. The components or features, methods, and Hardware for the execution of the process, the hardware and the product (product by process) This includes in combination with a production system incorporating

[0052] The systems, methods and devices disclosed herein each have several innovative aspects. and any single one of which alone is sufficient for the desirable attributes disclosed herein. Various system and method embodiments are described below. do.

[0053] (Efficient collection of multiple polarizations) Example 1 1. A system for characterizing a sample using second harmonic generation, comprising: a sample holder configured to support a sample; configured to direct a light beam at the sample to generate second harmonic generation, With one light source, first and second detectors configured to receive second harmonic generated light from the sample; an optical detection system comprising: said sample and said optical detection system for receiving second harmonic generated light from said sample; and a detector arranged in the optical path between the first and second polarized light components to separate the first and second polarized light components. at least one polarizing beam splitter, each of which directs the light beam toward the other; signals based on the received first and second polarization components from the first and second detectors; and an electronic device configured to receive the signal. Example 2 10. The system of claim 1, wherein the first and second polarization components comprise orthogonal polarization states. be. Example 3 The first and second polarized components include linearly polarized light having different polarization directions. The system described in Example 1 or 2. Example 4 The first and second polarized light components are s- and p-polarized light, respectively. The system according to any one of claims 1 to 5. Example 5 The at least one polarizing beam splitter includes a polarizing beam splitter cube. , the system described in any one of Examples 1 to 4. Example 6 a light source and a sample, the light source and the sample being disposed in a light path between the light source and the ... The system of any one of Examples 1 to 5, further comprising at least one polarizer. . Example 7 The at least one polarizer disposed in the optical path between the light source and the sample is 10 is the system described in Example 6, including a linear polarizer. Example 8 a light source disposed between the light source and the sample, for focusing light from the light source onto the sample; The system according to any one of Examples 1 to 7, further comprising at least one focusing lens. It is a system. Example 9 a second harmonic generation detector disposed between the sample and the polarizing beam splitter, Any of Examples 1 to 8, further comprising at least one collimating lens that collimates the raw light. The system according to any one of claims 1 to 5. Example 10 10. The system of any one of Examples 1 to 9, wherein the sample holder includes a translation stage. It is a system.

[0054] (SHG imaging) Example 1 1. A system for characterizing a sample using second harmonic generation, comprising: a sample holder configured to support a sample; configured to direct a light beam at the sample to generate second harmonic generation, With one light source, a light source for dividing the light from the light source into a plurality of beams, the light source being disposed in a light path between the light source and the sample; and incident on multiple locations on the sample at once, the multiple beams being multiple second harmonic at least one beam splitter configured to generate a wave generating signal; configured to receive second harmonic generated light from the sample, and configured to direct each of the SHG signals generated by the plurality of beams to a respective one of the beams, an optical detection system comprising a plurality of detectors; and processing electronics configured to receive signals from the plurality of detectors. Example 2 The at least one beam splitter receives a beam and splits the beam into a plurality of beam splitters. 10. The system of claim 1, further comprising a diffractive beam splitter configured to split the beam into a It is a system. Example 3 The at least one beam splitter receives a beam and splits the beam into a plurality of beam splitters. Any one of Examples 1-2, including an acousto-optic modulator configured to split the beam into The system is described in Example 4 The at least one beam splitter may direct an input beam to the sample. Any one of the first to third embodiments is configured to separate the output beams into three. This is a system. Example 5 The at least one beam splitter may direct an input beam to the sample. Any one of the first to fourth embodiments is configured to separate the output beams into five. This is a system. Example 6 The at least one beam splitter may direct an input beam to the sample. Any one of the first to fifth embodiments is configured to separate the output beams into ten beams. This is a system. Example 7 The system according to any one of Examples 1 to 6, wherein the plurality of detectors includes three detectors. It is a system. Example 8 The system according to any one of Examples 1 to 7, wherein the plurality of detectors includes five detectors. It is a system. Example 9 The system according to any one of Examples 1 to 8, wherein the plurality of detectors includes ten detectors. It is a system. Example 10 and providing at least one dichroic reflector in the optical path between the beam splitter and the sample. receiving the SHG signal from the sample and outputting the SHG signal to each of the plurality of detectors; The system according to any one of Examples 1 to 9, Example 11 The system according to any one of Examples 1 to 10, wherein the sample holder includes a translation stage. It is a stem. Example 12 a beam scanning system configured to scan the plurality of beams. The system is the system described in any one of Examples 1 to 11. Example 13 at least one polarized beam positioned to receive second harmonic generated light from the sample; and at least one polarizing beam splitter for splitting the light into first and second polarizing beamsplitters. and a second polarized component, and the first and second polarized components are respectively The system according to any one of Examples 1 to 12, configured to direct the be. Example 14 a plurality of polarizing beam splitters positioned to receive second harmonic generated light from the sample; the plurality of polarizing beam splitters splitting the light into first and second polarization components. and directing the first and second polarization components to first and second detectors, respectively. The system according to any one of the first to thirteenth embodiments is configured as follows. Example 15 The first and second polarization components are s- and p-polarized light, respectively. 14 is a system described in Example 16 1. A system for characterizing a sample using second harmonic generation, comprising: a sample holder configured to support a sample; configured to direct a light beam at the sample to generate second harmonic generation, With one light source, at least one detector configured to receive second harmonic generated light from the sample; an optical detection system comprising an array; a projection device configured to project second harmonic generated light from the sample onto the detector array; An optical system; and processing electronics configured to receive signals from the detector array. Example 17 17. The system of claim 16, wherein the at least one detector array comprises a two-dimensional array. is. Example 18 18. Any of embodiments 16-17, wherein the at least one detector array includes a CCD array. 1. The system according to claim 1. Example 19 19. Any of Examples 16-18, wherein the at least one detector array includes a time-dependent integrator. The system according to any one of claims 1 to 5. Example 20 The projection optics is configured to image the sample onto the detector array. The system is described in any one of Examples 16 to 19. Example 21 the projection optical system includes at least one imaging lens, and the at least one detector 21. The system of any one of Examples 16 to 20, wherein the array is located in a conjugate image plane of the sample. It is a stem. Example 22 at least one focusing element configured to focus light from the light source onto the sample; The system of any one of Examples 16 to 21, further comprising a lens. Example 23 a small number of detectors configured to translate the sample relative to the light source and the detector array; 23. The system of any one of Examples 16 to 22, further comprising at least one translation stage. It is a stem. Example 24 24. The method of claim 23, wherein the at least one translation stage includes an xy translation stage. This is a system. Example 25 At least one polarizing beam positioned to receive second harmonic generated light from the sample. the at least one polarizing beam splitter directs the light into a first and a second polarized component, and the first and second polarized components are respectively labeled as first and second polarized components. 25. The system of any one of Examples 16 to 24, configured to direct the system to two detector arrays. It is a stem. Example 26 At least one polarizing beam positioned to receive second harmonic generated light from the sample. the plurality of polarizing beam splitters splitting the light into first and second polarizing beam splitters; and separating the first and second polarization components into first and second detectors, respectively. The system according to any one of Examples 1 to 25, . Example 27 The first and second polarization components are s-polarized and p-polarized, respectively. or the system described in 26. Example 28 1. A system for characterizing a sample using second harmonic generation, comprising: a sample holder configured to support a sample; configured to direct a light beam at the sample to generate second harmonic generation, With one light source, a light source for dividing the light from the light source into a plurality of beams, the light source being disposed in a light path between the light source and the sample; and incident on multiple locations on the sample at once, the multiple beams being multiple second harmonic at least one beam splitter configured to generate a wave generating signal; configured to receive second harmonic generated light from the sample, Each of the SHG signals generated by the multiple beams from the splitter is an optical detection system including at least one detector array configured to direct the detector array toward the area; and, and processing electronics configured to receive signals from the plurality of detectors. Example 29 The at least one beam splitter receives a beam and splits the beam into a plurality of beam splitters. 29. The system of claim 28, further comprising a diffractive beam splitter configured to split the beam into It is a stem. Example 30 The at least one beam splitter receives a beam and splits the beam into a plurality of beam splitters. 30. Any of Examples 28-29, including an acousto-optic modulator configured to split the beam. 1. The system according to claim 1. Example 31 The at least one beam splitter directs one input beam to the sample. 31. Any of embodiments 28-30, configured to split into at least three output beams. 1. The system according to claim 1. Example 32 The at least one beam splitter directs one input beam to the sample. 32. Any of embodiments 28-31, configured to split into at least five output beams. 1. The system according to claim 1. Example 33 The at least one beam splitter directs one input beam to the sample. 33. Any of embodiments 28-32, configured to split into at least ten output beams. 1. The system according to claim 1. Example 34 34. Any of embodiments 28 to 33, wherein the at least one detector array includes a plurality of pixels. 1. The system according to claim 1. Example 35

[0023] In some embodiments, the region of the at least one detector array includes one or more pixels. 35. The system according to any one of items 28 to 34. Example 36 36. Any of Examples 28-35, wherein the at least one detector array includes a CCD detector array. The system according to any one of claims 1 to 5. Example 37 and providing at least one dichroic reflector in the optical path between the beam splitter and the sample. receiving the SHG signal from the sample and detecting the SHG signal from each of the at least one detector array; 37. The system of any one of Examples 28 to 36, wherein the SHG signal is directed to the region. is. Example 38 38. Any of embodiments 28-37, wherein the sample holder includes at least one translation stage. The system is as described in any one of claims 1 to 10. Example 39 a beam scanning system configured to scan the plurality of beams. The system is the system described in any one of Examples 28 to 38. Example 40 at least one polarized beam positioned to receive second harmonic generated light from the sample; and at least one polarizing beam splitter for splitting the light into first and second polarizing beamsplitters. and a second polarized component, and the first and second polarized components are respectively 39. The system of any one of Examples 28 to 39, configured to direct the detector array It is a system. Example 41 a plurality of polarizing beam splitters positioned to receive second harmonic generated light from the sample; the plurality of polarizing beam splitters splitting the light into first and second polarization components. and directing the first and second polarization components to first and second detectors, respectively. The system according to any one of Examples 28 to 40 is configured as follows. Example 42 40. The method of claim 40, wherein the first and second polarization components are s- and p-polarized light, respectively. 41 is a system according to [Brief explanation of the drawings]

[0055] The figures diagrammatically illustrate aspects of various embodiments of different variations of the invention. . [Figure 1A] FIG. 1A is a diagram of an embodiment of an SHG measurement system herein. [Figure 1B] FIG. 1B is a perspective view of a chuck for use in such an SHG system. [Figure 1C] FIG. 1C is a diagram of another SHG measurement system embodiment herein. [Figure 2] 2A and 2B illustrate an example of the use of a pump / probe system to generate a characteristic SHG signal. [Figure 3]3A and 3B illustrate an example of the use of a pump / probe system to generate a characteristic SHG signal. [Figure 4] FIG. 4 illustrates the use of a probe / pump system to determine the injection carrier energy threshold. [Figure 5] FIG. 5 is a flow chart detailing a method for generating the signals shown in the figure. [Figure 6A] FIG. 6A is a diagram of an embodiment of the system. [Figure 6B] FIG. 6B is a diagram of an embodiment of the system. [Figure 6C] FIG. 6C is a diagram of an embodiment of the system. [Figure 7] FIG. 7 is a diagram of the system functionality. [Figure 8A] FIG. 8A is a diagram depicting a method for providing such functionality. [Figure 8B] FIG. 8B is a diagram depicting a method for providing such functionality. [Figure 9] FIG. 9 is a diagrammatic representation of the system functionality. [Figure 10] FIG. 10 is a plot of an embodiment of the method related to SHG investigations. [Figure 11] FIG. 11 is a plot of an embodiment of the method related to SHG investigations. [Figure 12A] FIG. 12A is a plot of time dynamics associated with the system of FIG. 6C that can be used in the methods of FIGS. [Figure 12B] FIG. 12B is a plot of time dynamics associated with the system of FIG. 6C that can be used in the methods of FIGS. [Figure 12C] FIG. 12C is a plot of time dynamics associated with the system of FIG. 6C that can be used in the methods of FIGS. [Figure 12D] FIG. 12D is a plot of time dynamics associated with the system of FIG. 6C that can be used in the methods of FIGS. [Figure 12E] FIG. 12E is a plot of time dynamics associated with the system of FIG. 6C that can be used in the methods of FIGS. [Figure 13] FIG. 13 is a plot of a current-based probe method for observing transient electric field decay. [Figure 14] 14A and 14B are diagrams illustrating hardware configurations that can be used in the method of FIG. [Figure 15] 15A and 15B are schematic diagrams of SHG system components that can be used herein. [Figure 16A] FIG. 16A is a perspective view of a first chuck configuration herein. [Figure 16B] FIG. 16B is a side cross-sectional view of the chuck configuration of FIG. 16A. [Figure 17A] FIG. 17A is a cutaway perspective view of a second chuck configuration herein. [Figure 17B] FIG. 17B is a cutaway top view of a second chuck configuration herein. [Figure 17C] FIG. 17C is a cutaway perspective view of the chuck of FIGS. 17A / 17B. [Figure 18] 18A and 18B are diagrams of the AC voltage applied to the sample and the AC voltage that appears, excluding the DC bias probe. [Figure 19] 19A and 19B are diagrams of the AC voltage applied to and appearing on the sample to test for leakage current. [Figure 20] FIG. 20 shows an example of a schematic diagram of an SHG system that can be used to control the polarization of the light directed at the sample as well as the polarization of the SHG light collected from the sample. [Figure 21] FIG. 21 shows an example of a schematic diagram of an SHG system that includes a polarizing beam splitter so that first and second polarizations (eg, s- and p-polarized components) of the SHG signal can be collected simultaneously and separately. [Figure 22A]FIG. 22A shows an example of a schematic diagram of an SHG imaging system that includes a beam splitter configured to split a laser beam into multiple beams, each generating multiple SHG signals and capable of being directed to multiple detectors. [Figure 22B] FIG. 22B shows another example of a schematic diagram of an SHG imaging system that includes a beam splitter configured to split a laser beam into multiple beams, each generating multiple SHG signals and capable of being directed to multiple detectors. [Figure 23] FIG. 23 shows an example schematic of an SHG system that includes a detector array and optics configured to project light from multiple SHG signals from multiple locations on the sample onto the detector array. DETAILED DESCRIPTION OF THE INVENTION

[0056] (Part I) FIG. 1 is a diagram of a system 100 that may be used in connection with the subject method. For a variation of such a system, see U.S. Provisional Application No. 61 / 9808, filed April 17, 2014. In the specification of No. 60, "Wafer Metrology," Section II, "System and Method for Measuring Charge Decay," For example, suggestions are given regarding intermediate optics, the inclusion of optical delay lines, and optional electrode functions. be.

[0057] As shown, the system 100 includes a sample wafer 2 held by a vacuum chuck 30. 1 includes a primary or probe laser 10 that directs an interrogating beam 12 of electromagnetic radiation onto the As shown in B, the chuck 30 supports the x and y stages and, optionally, the laser. a rotation stage for positioning the sample location 22 across the wafer relative to where the sample is pointed; The xy stage allows other hardware Multiple wafer surface positions or locations 22 can be scanned without moving the wafer. The rotation stage allows for strain and related defects in the material to be characterized, if desired. It becomes possible to evaluate the influence of the crystal structure on SHG, such as defects or areas of concern. Any feature, aspect and / or use of the chuck 30, including, but not limited to, any of the following, as of April 1, 2014: Section IV of the specification of U.S. Provisional Application No. 61 / 980,860, filed on the 7th, entitled "Wafer Metrology Technology" The sample position 22 may include one or more layers. The sample position 22 can include a composite substrate including at least two layers. The material location 22 is used for the separation between two different materials (e.g., two different semiconductor materials, between two semiconductor materials, between a semiconductor and an oxide, between a semiconductor and a dielectric material, between a semiconductor and The interface may include an interface between a metal and an oxide, or between an oxide and a metal.

[0058] When using the system 100, the reflected radiation beam 14 towards the detector 40 is G signal. Detectors include photomultiplier tubes, CCD cameras, avalanche detectors, Whether it's a photodiode detector, a streak camera, or a silicon detector The system 100 may also include one or more shutter-type devices 50. The type of shutter hardware used may be used to block, dump, or otherwise block laser radiation. The time frame for the sample to be oriented away from the sample position is dependent on the method. Use electronic optical shutoff devices such as -9 ~10 -12 You can get a time of about 1 second.

[0059] Longer shut-off time intervals (e.g., about 10 -5 For longer than 100 seconds, a mechanical shutter or Alternatively, a flywheel chopper type device may be used. However, electro-optical isolators are not suitable. The device allows a wider range of substances to be tested according to the following method: Photon counting systems that can be opened and closed discretely at intervals, typically on the order of picoseconds to microseconds. The system 44 can be used to resolve time-dependent signal counts. In this case, an optical delay line can be incorporated as described above.

[0060] The system 100 may include an additional electromagnetic radiation source 60, also referred to as a pump source. In various embodiments, the radiation source 60 is shown as emitting a directional beam 62. or a UV flash that emits divergent or optically collimated pulses 64. In the case of a laser source, its beam 62 is collinear with beam 12. The light source may be a light source (e.g., redirected by an additional mirror or prism, etc.). The output wavelength of 60 can be anywhere from about 80 nm to about 1000 nm. Using shorter wavelengths (e.g., less than about 450 nm) produces fewer photons than longer wavelengths. It is possible to use and / or drive charge excitation at lower peak intensities.

[0061] For flash lamps, the energy per flash or the power consumed during the flash Levels may depend on substrate material. Total energy per flash 1J to 1 A flash lamp generating 0 kJ was used to generate a fully depleted silicon-on-insulator (F However, pulsed or constant UV light sources may also be used. The key factor in the properties and applications of the pump is the transfer of charge carriers to the induced Suitable flash lamp manufacturers include Hellm, USA. These include Company A and Hamamatsu Photonics Co., Ltd.

[0062] When a laser is used as the light source 60, nanosecond, picosecond, or femtosecond, or It could be any of the faster pulsed laser sources, or even a continuous solid state laser. In various embodiments, the pump source is wavelength tunable. The available choices include Spectra-Physics' Velocity and Vor tex Tunable Laser. In addition, tunable solid-state solutions are available. , available from LOTIS' LT-22xx series of solid-state lasers.

[0063] Whether provided as a laser or a flash lamp, the pump source 60 It may be selected to have a relatively high average power, which may be from about 10 mW to about 10 W. However, more typically, it ranges from about 100 mW to about 4 W, depending on the material under investigation (again, considerations apply). What is needed is a method for injecting charge carriers into material interfaces (e.g., dielectric interfaces). The pump source is a material-specific pumping source. The average power of 60 is selected to be below the threshold of optical damage to the material. For example, The pump source 60 may be configured to exceed the optical damage threshold of silicon when the investigated material includes silicon. To avoid this, the average optical power can be selected to be 1-2 W.

[0064] The probe laser 10 may be a nanosecond, picosecond, or femtosecond or faster pulse. Any commercially available laser source with the required peak power, wavelength, and reliability can be used. Two commercially available laser options are doped fiber and titanium sapphire devices. Hirent's VITESSE and Spectra-Physics' MAI TAI lasers is an example of a suitable titanium sapphire. Femtolasers and other manufacturers also , and other suitable Ti:sapphire devices. Suitable doped fiber lasers can be manufactured using IM Manufactured by RA, OneFive, and Toptica Photonics. Depending on the quality and pump type, many manufacturers, including Hamamatsu, offer picosecond and / or nanosecond pumps. Second-order lasers may also be an option. Lasers 10 have wavelengths from about 100 nm to about 2000 nm. It operates at a peak power of about 10kW to 1GW in the wavelength range, but the power supply is It may be less than 50mW.

[0065] Any of a variety of other so-called "intermediate" optical components may be used in system 100. For example, the system can detect reflected light directly from the laser 10 and / or light source 60. A dichroic reflective or refractive filter 70 selectively passes the radiation and the coaxial SHG signal. Alternatively, a prism can be used to convert the weaker SHG signal into a reflection that is orders of magnitude stronger. However, the prism approach is highly susceptible to misalignment. The dichroic systems described above may be preferred as they have always proven to be more sensitive. Other options include the use of a diffraction grating or a pellicle beam splitter. Alternatively, a filter wheel may be provided. 90, polarizer 92, and / or zoom lens 94 device or assembly. It can be used with systems that also offer angle (or arc) rotation adjustment (compatible with the detector). with adjustment) and in-line optics may be desirable.

[0066] In the implementation shown in FIG. 1C, the beam 12 from the laser 10 is split by a beam splitter 74. The beam splitter 74 can split the light into two paths by using an unequal For example, 70% of the energy of beam 12 may be split into a first path and a second path. (e.g., as beam 16) along the % can be directed along a second optical path (e.g., as beam 18). Thus, 60% of the energy of the beam 12 can be directed along the first optical path, and the beam As a further example, 40% of the energy of 12 can be directed along the second optical path. Thus, 80% of the energy of beam 12 can be directed along the first optical path, and 80% of the energy of beam 1 20% of the energy of 2 can be directed along the second path. Uneven (e.g., 70-30%, 80-20%, 60-40%, or any range in between) For example, 60-90% on one route and 40-10% on another route, and (and outside the range as well) and transmits most of the power to the pump beam and the rest to the probe beam. For example, the split can be 60-70% vs. 40% for the pump and probe, respectively. 0-30%, 70-80% vs. 30-20%, 80-90% vs. 20-10%, or 90- It can be 99.999% versus 10 to 0.001%. In different embodiments, for example, The beam is 0.001% to 49.99%, while the pump beam is 50.001% to 9 The sum of the two beams can be 100% or close to it. The partitioning may depend on the particular material system being characterized. In the example shown in Figure 1C, 5% of the beam energy of beam 12 is directed along the first optical path, and 95% of the beam energy is directed along the second optical path.

[0067] The beam splitter 74 may be a dielectric mirror, a splitter cube, a metallized mirror, a periphery, or any other suitable material. If the beam 12 contains optical pulses, it may include a mirror or a waveguide splitter. In this implementation, the beam splitter 74 separates the beam between the two optical paths to avoid spreading the light pulse. The optical element shown in FIG. 1C may include an optical component with negligible dispersion that splits the beam 12. Each beam is redirected or aimed using various mirror elements 72 so that It is possible.

[0068] The output from the detector 40 and / or photon counting system 44 is input to an electronic device 48. The electronic device 48 may be a computing device, a computer, a tablet, a microcomputer, The electronic device 48 may be a processor, a processing electronics, or an FPGA. Equipment, control electronics, processing / control electronics, or software (or software components) The operating system includes an electronic device that can be configured to execute the modules. In addition to running web browsers, phone applications, and email One or more programs, including any other software application The electronic device 48 may be configured to execute software applications such as The methods discussed herein may be implemented in machine-readable non-volatile memory such as RAM, ROM, EEPROM, etc. The electronic device 48 may be implemented by executing instructions contained on a temporary storage medium. a display and / or a graphic user interface for interacting with the user. The electronic device 48 can communicate with one or more devices via a network interface. The network interface can be, for example, a wired Ethernet , Bluetooth (registered trademark), or wireless connection, etc. The device may include a power supply and / or a transceiver.

[0069] As for the other options, the SHG signal is weak compared to the reflected beam that generates it. It is desirable to improve the signal-to-noise ratio of SHG counting. The counting gate time is reduced due to the blocking and / or delay processes described herein. As the number of noise sources increases, improvements become even more important. One method of reducing noise that may be used is The solution is to actively cool the photon counter. This can be done with extremely low temperatures such as liquid nitrogen or helium. This can be done using hot fluid or solid state cooling using a Peltier device. Areas of improvement include the use of a Marx Bank Circuit (MBC) linked to shutter speed. Additionally, the system 100 may be integrated in-line within a production line environment. The production line elements preceding or following the system 100 may include epitaxial layers. Axial growth systems, lithography and / or deposition (CVD, PVD, sputtering) Any of the above systems (e.g., networking, networking, etc.) may be included.

[0070] Now, Figures 2A / 2B and 3A / 3B show the pump / probe systems of interest. 2A and 2B are schematic diagrams showing examples of the types of SHG curves that may be obtained using the method. and 2B, the time scale for obtaining such a signal is milliseconds (10 -3 seconds) These are therefore "fast" processes. This potentially provides orders of magnitude improvement in time compared to existing methods. Before the G probe, a flash lamp is used to expose the entire surface of the test material to UV radiation. Dramatically reduces overall scan time as continuous measurements at do.

[0071] Specifically, the SHG signal 200 in Figure 2A is measured at an initial intensity 202. is generated by applying probe source radiation to the surface location. After a given time difference (O1) the signal strength increases with time. The SHG signal 206 in FIG. 00' is at a lower level 212 produced by the probe radiation only, and the time difference ( When the pump radiation is applied after O2, a higher plateau 216 appears along the time-dependent curve 214. The signals 200 and 200' also show time-dependent changes at the beginning and end of the curves. Contains components or parts that do not exist.

[0072] Both observations in Figures 2A and 2B are based on the substrate material of the target system and different laser powers ( For example, in this case, it can be made depending on the pump power. Charge separation involves electrons and holes separating from each other after excitation from a photon. Therefore, electrons injected from the silicon valence band into the SiO2 conduction band are mainly located at the top of the oxide surface. Most of the holes are trapped near the silicon valence band near the Si / SiO2 interface. This separation of charge carriers by excitation from incident radiation or internal photoemission is It contributes to the electric field present in the target system, which in turn modifies the measured SHG. This is due to various factors such as the presence of gaseous oxygen at the test site, the composition and structure of the sample in question, etc. This determines whether the observation shown in Figure 2A or 2B is made.

[0073] In fact, there are instances where the combination of signals 200 and 200' is observed. In general, the signal strength first drops from a peak, reaches a bottom, and then rises again to an asymptote. The SHG intensity curve is determined by the nonlinear susceptibility tensor, which is related to the molecular orientation. The charge carriers that move across the interface are affected by the atomic composition, electronic structure, and external fields. The rear changes the structure and charge state of the electric field in the layer below the interface where the SHG signal originates. Depending on the type of charge carriers across the surface (positive or negative) and the initial state of the electric field across the interface, The intensity of the detected SHG signal varies with the spot size. , average laser power, peak laser power, etc., and the system 100 , to detect SHG signals having intensities ranging from about 400 counts / second to about 7 million counts / second. The pump / probe systems described herein can be configured to This reduces the time required for the moving charge carriers to reach a saturation level. In various embodiments, the charge carriers moving across the interface reach a saturation level. The time required to generate the signal varies from 1 ms to 10 s in the pump / probe system described here. 00 seconds. When the charge carrier density in the region including the interface falls below saturation, When the charge carrier density in the region including the interface reaches a saturation level, the time of the SHG signal It may be advantageous to obtain inter-phase evolution, so the system can be configured to turn on / off the pump radiation. It can be configured to take SHG signal measurements within about 1 μsec after being turned off. For example, the system may be configured to turn the pump radiation (or probe radiation) on and off within 10 seconds. within approximately 6 seconds after turning the pump radiation on and off, and within approximately 1 second after turning the pump radiation on and off. Within approximately 100 ms after turning the pump radiation off / on, or within Within approximately 1 ms after turning the pump radiation on and off, and within approximately 1 μs after turning the pump radiation on and off. Formed within approximately 1 ns after turning the morphism off / on, or by one of these values Any range (e.g., greater than 1 ns, greater than 1 μs, greater than 1 ms, duration configured to acquire SHG signal measurements within, as well as outside, those ranges These values ​​and ranges can be applied to obtain data from a single point. However, by using appropriate imaging optics, this can be extended to cover a substantial area of ​​the wafer. As shown in the brackets above, these The values ​​and ranges of also apply to the probe radiation. The charging time and the required for acquiring the SHG signal This reduces the time required for testing interfaces, allowing for faster testing and / or manufacturing. The throughput of the production line can be improved.

[0074] For comparison, Figures 3A and 3B show a case where radiation is used to probe the substrate, as in existing SHG techniques. When using only one radiation source (in this case a high average power and high peak power laser) 3A and 3B are schematic diagrams of SHG signal curves 300 and 300′ for corresponding materials. The time scale for generating the SHG signal curves 300 and 300' in Fig. 3B is several Ten to several hundred (10 2 ) seconds.

[0075] Over such a time, these signals (such as those in Figures 2A and 2B) 302 and / or the lower and upper plateaus that can be characterized after the time-dependent signal 306, 316. In this way, similar (or identical) analyses can be performed on signals 200 / 200'. , and 300 / 300', but the main difference is the target system (i.e., a lower peak power femtosecond probe laser can be used for pre-excitation of the material. (used in conjunction with a high average power pump) can reduce the time it takes to obtain the desired signal information. Furthermore, the method in question allows for a significant improvement in time efficiency. An easier way to determine time-independent SHG measurements without using filters or other methods can provide the law.

[0076] In either case, Figure 4 shows how to determine the injected carrier energy threshold. In this case, the pump includes a tunable laser, which allows the light entering the sample from the pump to By increasing the output frequency (and therefore the energy by E=hν) of the photons over time after irradiation, The observed SHG activity is shown as signal 400. The pump laser is called 402. The initial SHG signal level generated by application of the probe laser, applied or used For example, if the signal has a sudden change (i.e., an inflection at 404, a discontinuity, a maximum, a minimum, a step function, Observe until you see a sudden change in frequency, peak, or slope. In various implementations, the energy threshold is considered to correspond to From the valence band of one semiconductor material to the conduction band of another semiconductor material, e.g. , or semiconductor materials and dielectric materials (e.g., Si and SiO2, Si and Si3 N4, Si and Ta2O5, Si and BaTiO3, Si and BaZrO3, Si and ZrO2, Si and HfO2, Si and La2O3, Si and Al2O3, Electrons cross the interface between two materials (e.g., Si and Y2O3, Si and ZrSiO4) The system 100 has a range of energy from about 1.0 eV to about 6.0 e The device can be configured to measure energy thresholds in the range of V. The system and method may be used for, for example, bonding between two different semiconductors, between a semiconductor and a metal, or between a semiconductor and a metal. and determining the energy thresholds of various interfaces, such as between dielectrics. It is possible.

[0077] FIG. 5 is a flow chart illustrating the implementation of a method for characterizing semiconductor devices using SHG. 5 is a chart showing various process flow paths. All such methods are One may begin by positioning the specimen at a desired location (e.g., typically a wafer By positioning the chuck 30 after the chuck 20 is fixed. (i.e., repositioning) of any SHG detection event 520, as will be further explained. may occur at multiple surface locations or at all surface locations within the area of ​​the sample, Or to scan all the surface positions of the sample. , which may occur after making a given decision at 540 regarding the detected SHG signal ("Back" selection (Both are shown with dotted lines.) For further details regarding the alternative decisions, see the above-referenced publication. In either case, the positioning or Selects a specific flow path following repositioning (or selects a different flow path for the same It can also be run consecutively at surface locations to generate different data).

[0078] According to one process flow path (solid line), probe source radiation is introduced at 504 into a specific field. The pump source radiation is then applied at 506. For pump radiation, the photon energy can be increased (if necessary) by decreasing the radiation wavelength. The resulting SHG is detected at 520. 42, signal analysis (based on the example in Figure 4) allows the determination of the carrier injection energy threshold. In various implementations, the energy of the pump radiation is measured at the energy threshold of the semiconductor interface. Therefore, the energy of the pump radiation is set to about 1.0 eV to about 6.0 eV. For example, to determine the energy threshold across the Si and SiO2 interface, The energy threshold of pump radiation can be varied from about 4.1 eV to about 5.7 eV. The change in energy is achieved by changing the frequency (or wavelength) of the radiation. For example, a sample with an expected energy threshold of about 3.2 eV can be investigated. To achieve this, the wavelength of the pump radiation can be varied from about 443 nm to about 365 nm. In various implementations, photons of pump radiation can generate electrons with twice the energy Therefore (for example, when one electron absorbs two photons), the energy of the pump radiation is This may be below the energy threshold of the conductor interface. Longer charging times allow for observations with improved resolution and intensity. This can increase the time required to test a sample location and reduce throughput.

[0079] According to an alternative process flow path (dashed line), pump radiation is applied to the substrate at 508. Such applications can be performed by directly investigating only the surface (e.g., by laser) or by scanning the wafer. The entire surface of the device can then be irradiated with light (e.g., using a flash lamp). At 520°C, the portion of the sample under investigation is exposed to the radiation of the probe source. The resulting SHG is measured at 520°C. For the pump-probe-detection aspect of the method, thereafter, potentially at 502 After repositioning the sample, it may be repeated. However, as shown, operation box 50 Step 8 can be omitted, and if the entire substrate is first exposed to radiation, as in the example above, Some pumps may be bypassed or omitted from the sequential scanning process. In addition, various SHG-based signal analyses are performed at 544, as described elsewhere in this application. Thus, decisions other than the energy threshold determination of block 542 may be made.

[0080] Following an alternative process flow path (dashed line), probe radiation at 504 and 510 Immediately after applying the irradiation, the SHG signal data was collected at 520, while the pump irradiation at 508 was performed at 50 4 and 510 probe probes are performed. Again, the method is performed recursively to Sample multiple locations, such as all parts of the area, and then use flowchart element 502 Return, reposition, and then probe-detect-pump-probe-detect method or part thereof can be repeated.

[0081] In particular, the method or part of the method for SHG signal analysis (generally boxes 540 and 542 (included in the above) in real time, such as with instantaneous or near-instantaneous output In doing so, any spectroscopic properties determined by the collected data can be by software packages either on-line or through remote integrated software. Alternatively, the SHG signal analysis can be performed on some or all of the SHG data. After detection or collection, the signals may be processed in post-processing.

[0082] For the systems and methods described herein, a specimen (e.g., a semiconductor wafer or For example, the systems and methods described herein can be used to characterize the The method can be used to detect defects or contaminants in a sample as described above. The system and method described herein are used to characterize specimens during semiconductor wafer manufacturing or production. Accordingly, the system and method may be adapted to The systems and methods described herein can be used along the semiconductor manufacturing / production The systems and methods described herein can be integrated into automated wafer processing lines. For example, the system can be integrated into a semiconductor manufacturing line with front-office processing capabilities. Equipment floors that accept wafer cassettes such as Feeder Unified Pods (FOUPs) These cassettes can be fitted with an EFEM. Each is processed by a human operator or by moving the cassette along a manufacturing / production line. These are delivered to these machines by automated cassette handling robots that move them from process to process. can.

[0083] In various embodiments, the system comprises: once the cassette is mounted on the EFEM: The FOUP opens and the robot arm selects individual wafers from the FOUP and inserts them into the system. The light-tight process box and vial are transported through an automatically operating door. The chuck can be configured to accommodate a sample placed on it. It can be designed to complement and fit with the robot arm so that it can At some point during the process, the wafer can be held up to a scanner to identify the unique laser markings.

[0084] Therefore, systems configured to be integrated into semiconductor manufacturing / assembly lines: Automated wafer handling capability from FOUP or other types of cassettes to EFEM as above integration of the chuck and robot rod / arm, designed in a way that is compatible with robotic manipulation Automatic light-blocking door that opens and closes to allow for wafer loading / unloading and It may have software that signals the EFEM for wafer identification.

[0085] (Part II) 6A shows a first system 2100 that may be used in connection with the subject method. Systems 2100' and 2100'' are shown in Figures 6B and 6C. Each system includes a vacuum chamber. A primary beam of electromagnetic radiation 2012 is directed at a sample wafer 2020 held by a rack 2030. The chuck 2030 includes the x and y stages and Position the sample position 2022 across the wafer as needed relative to where the laser is pointed. The detector may also include a rotation stage for determining the position of the object, or may be mounted on such a stage. The reflected radiation beam 2014 towards the detector 2040 will contain an SHG signal. photomultiplier tubes, CCD cameras, avalanche detectors, photodiode detectors, and The sample position 2022 may be either a leak camera or a silicon detector. The sample location 2022 may include at least two layers. The sample position 2022 may include a composite substrate. between semiconductor materials with different impurities; between semiconductors and oxides; This includes interfaces between conductors and dielectric materials, semiconductors and metals, or oxides and metals. It is possible.

[0086] Also, each embodiment has in common that it includes one or more shutter-type devices 2050. These are used as described in connection with the following methods: The type of hardware used may be to block, dump, or otherwise direct laser radiation away from the sample position. The time frame for moving away from

[0087] Using an electro-optical blocking device such as a Pockels cell or Kerr cell, a very short blocking period can be achieved. (i.e., the switching time is 10 -9 ~10 -12 You can get it in about seconds. Longer shut-off time intervals (e.g., about 10 -5 For longer than 100 seconds, a mechanical shutter or flash is required. A lye wheel chopper type device may be used.

[0088] However, the use of an electronic optical interceptor allows testing of a wider range of materials in the following manner: It will be possible to test it at very short time intervals, typically on the order of picoseconds to microseconds. Uses a photon counting system 2044 that can be opened and closed to resolve counting of time-dependent signals It is possible.

[0089] The hardware is intended to push the above method into a faster timeframe. That is, as shown in FIG. 6C, the system may include delay line hardware 2060. Beams between multiple time-set delay lines for a corresponding number of time-delayed interrogation events can be generated. It is possible to split and switch between frames (or turn the shutter on / off). The wire extension occurs immediately after the pump pulse (in most methods, only 10 -12 Only a second delay is needed Multiple transient charge decay probe events ranging from time frames of tens of nanoseconds to tens of nanoseconds (although sometimes not) This may be preferable as it provides a single solution for When using a repetitive laser, the desired delay time can be in the microsecond range. And such hardware may be used to implement the subject method (method and such hardware). Both the hardware and the Although uniquely suited, it may also be used for other purposes.

[0090] In the implementation shown in FIG. 6C, a beam 2012 from a laser 2010 is split into two beams by a beam splitter 2 The beam splitter 2070 splits the light into two paths. For example, the energy of beam 2012 may be divided unevenly between the optical paths. 70% of the light may be directed along a first optical path (e.g., as beam 2016); 30% of the energy of beam 2012 is directed along a second optical path (e.g., beam 2018 As another example, 60% of the energy of beam 2012 can be directed 1 path, and directs 40% of the energy of beam 2012 along a second path. As yet another example, 80% of the energy of beam 2012 can be directed along % of the energy of beam 2012 can be directed along a first optical path, and 20% of the energy of beam 2012 can be directed along a second optical path. The beam splitter 2070 can be a dielectric mirror, a splitter, or a beam splitter. May include a splitter cube, metallized mirror, pellicle mirror or waveguide splitter In an implementation where beam 2012 contains optical pulses, beam splitter 2070 , splitting the beam 2012 between two optical paths so as not to broaden the light pulse, negligible As shown by the double arrow in FIG. 6C, the primary beam 20 The path of the survey beam 2016 extracted from 12 by the beam splitter 2070 is: Lengthen or shorten to change arrival timing relative to the "pump" beam 2018 Each beam can be redirected or illuminated using various mirror elements 2072. Another approach (mentioned above) is to use optical delay elements and / or Other optical paths use optical fibers (e.g., as proposed in U.S. Pat. No. 6,819,844). and such description is incorporated herein by reference in its entirety).

[0091] The output from the detector 2040 and / or photon counting system 2044 is transmitted to the electronic device 20 48 (see, for example, FIGS. 6A and 6B). 48 is a computing device, computer, tablet, microcontroller or FPGA The electronic device 2048 may include a processor, processing electronics, control electronics, processing management / control electronics or to execute one or more software modules In addition to running an operating system, The processor may be a web browser, phone application, email program, or other One or more software applications, including any software application The electronic device 2048 may be configured to perform the methods discussed herein, e.g. For example, the information contained in a machine-readable non-transitory storage medium such as RAM, ROM, EEPROM, etc. The electronic device 48 may be implemented by executing instructions. The electronic device 2 may include a display and / or a graphic user interface. 048 can communicate with one or more devices via a network interface. A network interface is a transmitter that can communicate via wired or wireless connections. , a receiver, and / or a transceiver.

[0092] Another potential aspect of system 2100'' is the way the initial beam splitter operates. That is, uneven division (e.g., 70-30%, 80-20%, 60-40%) Or any range in between, for example, 60-90% in one route and 40-10% in another. (and also outside these ranges) and direct most of the power to the pump beam, For example, the splitting can be done by splitting the pump and probe beams separately. In contrast, 60-70% vs. 40-30%, 70-80% vs. 30-20%, and 80-90% vs. 2 It can be 0-10%, or 90-99.999% vs. 10-0.001%. In this configuration, for example, the probe beam is 0.001% to 49.99%, while the pump beam is The two beams can be 50.001% to 99.999%. The sum of the two beams is 100% or can be close to that value. The splitting is determined by the particular material system being characterized. The value of doing so is (at least in part) due to the material 10 and 11, which desirably reduces or minimizes the power involved in the SHG investigation following charging of the 11 and 12. The solution is to introduce the pump and probe beams at different angles. The technique facilitates separate measurement of the pump and probe SHG responses. In such cases, it may be advantageous to use two detectors, one for each reflected beam path. be.

[0093] The illustrated embodiment may be distinguished by various other optional optical systems. For example, Example 2 100 and 2100' are the directly reflected radiation from the laser 2010 and the coaxial SHG signal. 20. The optical fiber 200 includes a dichroic reflective or refractive filter 2080 that selectively passes a signal. Alternatively, a prism can be used to separate the weaker SHG signal from the reflected primary beam, which is orders of magnitude stronger. However, prism-based methods are very sensitive to misalignment. The dichroic systems described above may be preferred because they have been shown to , including the use of a diffraction grating or pellicle beam splitter. A light beam 2082 for focusing and collimating / cylindrical structure optics may be provided. As shown in system 2100', a filter wheel 2084, a zoom lens 2086, and A polarizer 2088 may also be used in the system. So, angle (or arc type) rotation adjustment (with corresponding adjustment of the detector) and Line optics may be desirable. Also, an additional radiation source 2090 (directional beam 2 Whether the laser shown emits 092, diverging or optically collimated, or focused, Incorporate a UV flash lamp (e.g., a UV flash lamp emitting pulsed 2094 light) into the system. U.S. Provisional Application No. 61 / 980,860, filed April 17, 2014, entitled "Wafer Metrology Technology" The features referenced above in connection with Section I of the "Pump and Probe SHG Measurements" and / or may provide initial charging / saturation in the following manner:

[0094] In these systems, the laser 2010 emits light in the wavelength range of about 700 nm to about 2000 nm. Although it has a peak power of about 10kW to 1GW, it provides an average power of less than about 100mW. In various embodiments, an average power of 10 mW to 10 W may be sufficient. The source 2090 (whether another laser or a flash lamp) emits light from about 80 nm to about 8 It can operate at an average power of approximately 10 mW to 10 W in the wavelength range of 1000 nm. Values ​​outside the ranges given above are also possible.

[0095] For other system options, the SHG signal is measured relative to the reflected beam that generates it. Therefore, it is desirable to improve the signal-to-noise ratio of SHG counting. As the time between the two decreases due to the blocking and / or delaying processes described herein, the improvement One way to reduce noise that may be used is to The key is to actively cool it. Cooling reduces the random photon errors caused by thermal noise. This can be achieved by using cryogenic fluids such as liquid nitrogen or helium, or by using a Peltier device. Other areas of improvement include the use of solid-state cooling using shutter speeds. This may involve the use of a Marx-Bank circuit (MBC) associated with the speed.

[0096] These improvements may be applied to any of the systems of Figures 6A-6C. Any or all of the above functions associated with 2100 and 2100' may be implemented by the system 2100. In fact, you can combine functions or parts between all systems. The plan is to:

[0097] Such a system implementing the subject method can be used to make a variety of decisions that were previously impossible. This can be done using laser blocking and / or delay techniques. 22 shows a process map or decision tree 2200 that represents such possibilities. For any detected defects 2210, defects (bonded voids, dislocations, particles of crystalline origin) extended defects such as point defects (COPs), and contaminants (e.g., copper or other metals mixed into point defects) Regarding defects, it is possible to analyze between defect types. 2 and / or quantification 2224 (e.g., density or extent) of defects can be determined. With respect to pollutants, the species or type of pollutant2232 and / or quantification of the pollutant 2234 determination is possible. Such analysis and species discrimination between defects and contaminants charge carrier lifetime, trap energy, trap capture cross section and / or Determine trap densities and then compare these with values ​​in a look-up table or database. Basically, these tables or databases can be used to compare contains a list of the properties of the material as characterized by the method of interest, and then specifies The properties are then converted into table or database entries corresponding to specific defects or contaminants. Compare with.

[0098] The trap capture cross section and trap density are related to the detected charging rate, if necessary. The determination of charge carrier lifetimes and trap energies is discussed by I. Lu. The following formula, based on the work of Andstrom, provides some guidance:

number

[0099] In either case, decay curve data from the samples under investigation are used to develop physical models and By utilizing the associated mathematics, the performance of trap energies and charge carrier lifetimes can be calculated. The parameters can be determined by the curves 2300, 2300 as shown in Figures 8A and 8B. A representative set of ' can be calculated from the above formula (Figure 8B shows a portion of the data in Figure 8A). (These are examples where the parts are highlighted or enlarged.)

[0100] These curves show the relationship between time constant (vertical axis) and dielectric thickness (horizontal axis) for different traps. The vertical axis shows the ultra-high energy, which is reduced to nanoseconds (1E-9 seconds). The horizontal axis represents the tunneling distance (or dielectric thickness, in this example both terms are The different curves are lines of steady state barrier energy. For example, in Figure 8B is the charge trapped in a listed trap with a barrier energy of 0.7 eV and an energy depth of 0.7 eV. The detrapping time is approximately 1E-5 seconds for a dielectric thickness of 40 angstroms (Å). Indicates a constant.

[0101] Further modeling can be done using Poisson / transport solvers, and MOS-like structures can be implemented. The trap densities of the structures and more exotic devices are compared with the charge carrier lifetime and known trap energies. Specifically, the optical injection current generated by a femtosecond optical pulse can be used to determine the This induces a burst of charge carriers that reach the dielectric conduction band. The average value of this current is The electric field across the interface can be related to the carrier concentration and lifetime in the region. is a proxy for measuring these phenomena.

[0102] In the plot of FIG. 8A, the 20 Å oxide has a track with an energy of about 3 eV. It can be observed that the discharge time constant for the loop is 1 ms (see dashed line). To relate this plot to a system application example, after cutting off the laser excitation, a 20 Å oxide As shown in Figure 8B (see highlighted box), the results range from 1 μs to approximately There is an observable current for up to 1 ms, after which all current disappears.

[0103] The decay curves discussed in this application have different energies and different relaxation / recombination time constants. This can be the result of multiple processes (e.g., charge relaxation, charge recombination, etc.) from traps that Nevertheless, in various embodiments, the decay curve is generally expressed as an exponential function f(t )=Aexp(-λt)+B, where A is the damping amplitude and B is the reference offset constant. , and λ is the decay constant. Using this general exponential function, the experimentally obtained decay The "degree of decay" can be estimated from the data curve. term 1 / 2 , mean lifetime τ, and decay constant λ are used to calculate the decay curve (experimental or simulated). It is possible to characterize the degree of attenuation of the signal (obtained by the modulation). For example, The parameters A, B, and λ are determined by the experimentally obtained attenuation data points, as described below. The mean lifetime τ can then be obtained for what we qualitatively call partial or complete decay. Using the theory of radioactive decay as a way to set standards, we calculate from A, B, and λ. For example, in some embodiments, τ can be expressed as 1 / 2 ) / (ln( 2)) can be given.

[0104] In various implementations, the state of charge is considered to be fully decayed after a period of three times the mean lifetime τ. This corresponds to a decay of ~95% from full saturation. Partial decay is particularly pronounced for the mean life It can be expressed as the signal after a certain multiple of τ has elapsed.

[0105] In operation, the system performs, at least in part, a step of: For each point on a portion (e.g., a die-sized portion) or the entire wafer, parameters (e.g., , carrier lifetime, trap energy, trap cross section, charge carrier density, trap voltage charge density, carrier injection energy threshold, charge carrier lifetime, charge storage time, etc.) The entire wafer (depending on the material, surface area, and required scan density) can be scanned in many cases. In this case, the scan can be performed in less than 10 minutes, and these parameters can be determined for each point scanned. In various embodiments, one location on the wafer is subjected to a time interval of about 100 ms to about 3 seconds. For example, one location on a wafer can be scanned in approximately 950 ms. do.

[0106] Quantitative analysis of each parameter was performed on the matrix data containing the spatial distribution of the determined parameters. Individual color-coded heat maps or graphs are used as a means of auditing, feedback, and reporting. This can be plotted on a contour map. Figure 9 shows such a map 2400. It shows how the defect 2402 may be depicted. Once quantitative data is available, it is possible to Providing the desired output is simply a matter of modifying the code in your plotting program / script. It is a matter of

[0107] Such information and / or other information may be processed by computer programs as follows: can be displayed on the monitor or dedicated system display and / or later It may be recorded on digital media for reference or use in analysis. The ellipsometry data is then used to correct for layer thickness variations for the spatial distribution of each wafer. Referenced and cross-correlated, and analyzed using, for example, total reflection X-ray fluorescence (TXRF), time-of-flight secondary ions Cross-calibration with independent contamination characteristics data obtained by mass spectrometry (TOF-SIMS) etc. These initial or modified spatial distributions can then be verified to be within specifications. Compared with the known spatial distribution of the wafer, the sample in question is found to have defects or defects that require further testing. However, in general, low-cost S HG, and other methods herein that use slow and expensive direct methods such as TXRF, It is desirable to use a meter that is calibrated against the meter.

[0108] Human decisions are initially made when determining the criteria for what wafers are acceptable or unsatisfactory. until the tool is properly calibrated and able to flag wafers autonomously. , and may be used (e.g., in a generated heatmap 2400 examination). For well-characterized processes in a factory, the only human decision required is to flag Identify root causes of systemic yield issues based on validated wafer characteristics This is probably because

[0109] However implemented, FIG. 10 is a flowchart illustrating a first method embodiment of the present invention. The method provides a method 2500 that can be used in making such a determination. Similar to other methods described and illustrated below, multiple shutters are used to open and close the interrogation laser for a period of time. This method relies on characterizing the SHG response using target blocking events.

[0110] In this first example, the part of the sample to be investigated is filled to saturation (usually by a laser). In this example, a single beam is used to generate the pump and probe beams. In other embodiments, separate pump and probe sources may be used. During this time, the SHG signal can be monitored. The saturation level is useful for characterizing and and / or charging-related SHG signal strength (I ch ) by observing the asymptotic behavior of Once saturation is reached (or afterwards), the electromagnetic radiation from the laser (pump beam) The laser (probe beam) is turned on for a selected period (t bl1 ) After the opening and closing stops, a laser (probe beam) is used to expose the surface. G intensity measurement (I dch1 ) and observe the decay of the charge at the first discharge point. part for a certain period (t ch ) to saturation (using the pump beam), The second interruption event is set at a different time (t bl2 ) and composite attenuation Identify another point along the curve. Unblock the laser (probe beam) and SHG Signal Strength (I dch2 ) is measured again. This decreased signal indicates a second opening or closing event. shows the decay of charge during the cut-off interval. The charge is recharged to saturation by the laser (pump beam). Then, a third interruption event (t bl3 ) followed by SHG survey and Signal Strength Measurement (I dch3 ) to obtain the third order of charge decay related to the SHG intensity. Measurements are taken.

[0111] In the above example, the sample is charged to a saturation level, but in other examples, the sample is charged to a charge level below saturation. In the above example, the three interruption times t bl1 , t bl2 , and t bl 3 is different, but in another example, three cutoff times t bl1 , t bl2 , and t bl3 The same In various examples, the sample can be initially charged to a certain charge level, and the SHG intensity Measurement value (I dch1 ), (I dch2 ) and (I dch3 ) after the first charging event can be obtained at different time intervals.

[0112] Referring to the above, these three points (I dch1 , I dch2 and I dch3 (corresponding to can be used to construct a composite charge decay curve, which is referred to herein as its constituent elements. We call it a "composite" curve because its elements come from multiple related phenomena. Repeat (possibility to generate more decay curve data points using different opening and closing times, or to check the accuracy and / or remove errors from the measurements of selected points (This is likely due to the timing of the same relationship) and after four or more cutoffs It may use a cycle of detection, but only two such cycles. It should be noted that one point in the decay-related data is the It does not provide a characterization of the decay curve, but rather models or extrapolates the curve to define a specific line. Points provide usefulness, and three or more points for exponential decay fitting are better. In other words, any simple damping motion (e.g., dispersion) Measurable (unless extended by transport physics) has the following general formula: t) = M0 * EXP(-t / tau). Then, the two unknown parameters M0 and tau To find the variance (i.e., In nonlinear motion, if you measure n points and apply a model appropriate to the order of approximation, It is desirable to measure as many points as possible to extract the (n-1)th correction parameter. Also, for that set of measurements, it is necessary to be very specific about the tau to assign to a particular type of defect. Measurements are taken for a range of electric fields (E) as is practical and accurate.

[0113] In the above method, measurements are taken at several time points to determine the parameter versus time (e.g. , interface leakage current or occupied trap density versus time) kinetic curves can be provided. The time constant (τ) can be extracted from the kinetic curve of the parameter versus time. This may be due to the time constant characteristics of the defect.

[0114] In either case, attenuation-dependent data acquisition is preceded by a probe (or probe). SHG data acquisition can be performed while saturating the material with a laser, but charging is not required. This does not necessarily mean that the laser will be saturated (e.g., as noted above). Furthermore, charging is not necessarily done with a survey / probe laser. (See, e.g., the optional pump / probe laser methodology cited above. (This refers to

[0115] Regardless, after target testing at one sample location, the sample material is usually transferred to the same (or or similar) to another part for testing, or to move it around. Alternatively, the entire wafer may be scanned as described above, even if multiple or all portions of the sample material are scanned. This can be investigated and quantified when conducting a scan.

[0116] FIG. 11 and plot 2600 are used to obtain charge decay related data through scanning. This method uses an alternative (or complementary) approach, where the battery is first charged to saturation and then charged to multiple The interruption time interval (t bl1 , t bl2 , t bl3 ) run (or at least semi-run) (Continued) For the discharge, the SHG intensity (I dch1 , I dch2 , I dch3 ) is measured The probe is probed by laser pulses from a probe / probe laser. the intensity and / or frequency of the laser pulses from the probe, the average power of the interrogation / probe laser, The SHG signal is reduced to avoid recharging the material while still obtaining a reasonable SHG signal during the cut-off time interval. To do so, only 1 to 3 laser pulses can be applied. Such reductions (in number and / or power) may be The material excitations resulting from the laser pulses can be ignored or calibrated and / or This can be taken into account when modeling.

[0117] In various embodiments, a separate pump source can be used for charging. In some embodiments, the probe beam can be used to charge the sample.

[0118] In both cases, the delay between pulses is the same or the expected transient charge This can be adjusted to take into account the attenuation profile or other practical considerations. Although this has been described in terms of "interruption" or "blocking," as discussed above in relation to Figure 6C, the delay It should be understood that the above-described signal may be generated using one or more optical delay lines. The same may be true for the blocking / switching discussed in relation to FIG.

[0119] As mentioned above, in Figure 11, the number of interruptions, delay time, or event type The SHG signal can be measured by charging it to saturation. In either case, the method of Figure 11 is used for the final development. This can be done so that the SHG signal is 0 during the closed period (as shown in the figure). To do this, check the charging strength (I ch Repeat this method in the mode that measures Or simply observe the SHG signal as it (re)charges to saturation.

[0120] 12A-12E illustrate a method for obtaining attenuation-related data points using the target hardware. FIG. 12A shows a series of laser pulses 2702, with Alternating pulses are used to trigger interrupt hardware in a so-called "pulse picking" technique (e.g., 2700, which is interrupted by a It is possible to pass some pulses (shown as solid lines) and block others (shown as dashed lines). is.

[0121] Figure 12B shows the resolution of the blocking technique for SHG investigations, as a function of the repetition rate of the probe laser. We provide a diagram 2710 illustrating how the REP can be restricted. Specifically, When a decay curve such as decay curve 2712 is exhibited, it operates on the same time scale as FIG. 12A. Using laser pulses shown as It is possible to split the file, however, the shorter curve 2714 is Therefore, the use of an optical delay stage provides a more efficient It is effective.

[0122] Next, diagram 2720 of FIG. 12C shows the interruption and delay relative to the reference time associated with charging the sample. By introducing the eigenvalue, we can obtain a useful overlap region for the decay time of the curves versus the laser repetition rate. We show (graphically and textually) how this can be achieved. Also, we show how the attenuation can be achieved by delay stages alone. Short time range over which the curve can be investigated, as well as blocking of the pump and / or probe beams We also show how there are longer time ranges where only 100% is practical.

[0123] Figures 12D and 12E further demonstrate the utility of a combined blocking / delay device. 730 shows an example of an SHG signal generated by an individual laser pulse 2702. Using only steps, you can vary the optical delay only by the range (X) between each such pulse. In contrast, the use of additional delay stages over the range (Y) can be investigated by and incorporating blocking or shuttering means such as a chopper, shutter, or modulator. This can be achieved with a combined system. As shown in FIG. 2740, such a system allows Decay curves (and associated time constants) ranging from one to several pulse times can be measured.

[0124] Figure 13 provides a diagram 2800 illustrating a third method embodiment of the present disclosure. The state is similar to that of Figure 11 except for the following: the discharge current (J dch1 , J d ch2 , J dch3 ), the material is charged with a laser (if necessary, its SHG intensity (I ch ) signal monitoring or capture) or other electromagnetic radiation source and then laser the time interval after which the device is allowed to discharge by shutting off or otherwise ceasing its application. (For example, basically, t follows a logarithmic time scale relative to linear time.) i =t0, 2t0, 3t0, 7t0, 10t0, 20t0, 30t0, 70t0, where t0 is approximately 10 - 6 Seconds or 10 -3 The time scale parameter is in seconds and is measured at the time the measurement was started. This method is similar to the conventional method except that the eh plasma in the substrate decays and then The moment when the current begins to appear allows us to estimate the lifetime of mobile carriers in the substrate. The important physical parameters of the carriers are obtained. After determining the carrier lifetime, the discharge current is The time dependence of the discharged charge (and This allows us to interpret the dynamics of charge decay.

[0125] Various embodiments can be used to measure time constants (such as decay) over a range of values. For example, the time constant can be set to 0.1 femto (f) seconds to 1f seconds, 1f seconds to 10f seconds, or 10f seconds. seconds to 100fs, 100fs to 1 pico(p)s, 1ps to 10ps, 10ps to 100p Seconds, 100p seconds to 1 nano (n) seconds, 1n seconds to 10n seconds, 10n seconds to 100n seconds, 100n Seconds to 1 microsecond, 1 microsecond to 100 microseconds, 100 microseconds to 1 millisecond, 1 millisecond and above Between 100 ms, 100 ms to 1 s, 1 s to 10 s, or 10 s to 100 s, or It can be in a larger or smaller range. The time delay (Δ) between the pump and probe is, for example, 0.1 fs to 1 fs, 1 f seconds to 10f seconds, 10f seconds to 100f seconds, 100f seconds to 1 pico(p) second, 1p second to 10p Seconds, 10psec to 100psec, 100psec to 1 nanosecond (n), 1nsec to 10nsec, 10nsec ~100nsec, 100nsec~1 microsecond, 1μsec~100μsec, 100μsec~1 Milliseconds (msec), 1msec to 100msec, 100msec to 1 second, 1 second to 10 seconds, or 10 seconds Can be between ~100 seconds. Values ​​outside these ranges are also possible.

[0126] A variety of physical techniques can be used to provide an optimal system for carrying out the method of FIG. , the method can be modified as described above. Two such methods are shown in Figure 1 4A and 14B.

[0127] Systems 2900 and 2900' use gate electrodes 2910 and 2920, Each electrode is made of a conductive material that is transparent in the visible light range. There is a possibility that they may come into contact with 2020, but they may be separated by a minimum distance and will not necessarily come into contact. In various implementations, the electric field of the dielectric is expressed as a capacitance-voltage AC measurements of the curves (CV curves) can be used to extract the electrode-dielectric-substrate structure parameters. The CV curve measurement is performed by connecting a material sample to the tool of interest and measuring the temperature using a commercially available standard This can be done using a CV measurement device (e.g., applying a voltage of about 0.1 MV / (This can provide an electric field of about 5 MV / cm to about 5 MV / cm). It can be held on an electric chuck 2030. Another alternative structure for the gate electrode is a 10-30 There is an ultra-thin Au or Al film on glass with a thickness of Å, and some of it is covered with a thin semi-transparent metal layer. The absorption of photons can reduce sensitivity.

[0128] However, electrodes 2910 and 2920 do not present absorption problems (although calibration If so, can it be solved or can be considered within the system, refraction-based considerations may arise. These electrodes are made of ZnO, SnO, etc., connected to electrical contacts 2932. The transparent conductive gate layer 2930 may be made of a material. The gate layer 2930 may be formed as shown with a thickness (D gc ) dielectric (Si The transparent carrier 2936 may be made of O2. The rear includes an insulator used as a gate for a non-contact electrode, the non-contact electrode being 201 The specification of U.S. Provisional Application No. 61 / 980,860, filed April 17, 2004, entitled "Wafer Measurement Technology" To perform electrical measurements similar to those described in Section IV, "Field-Biased SHG Techniques," For example, capacitive coupling can be used: the wafer is charged from the incident laser radiation, and then The electric field across one or more of the interfaces of the wafer changes, and the layers of the wafer act as plate capacitors. Similarly, there is capacitive coupling to the plates in the electrode. Charging the electrode is measured as a current. This is accompanied by the movement of charge carriers.

[0129] D gcBy measuring the CV curve on the semiconductor substrate using a non-invasive method, The applied voltage will be known and used to calculate the electric field (E). If the gap distance between the electrode and the sample is negligible, it may be an air gap. The probe can be in direct contact with the sample, rather than being separated by an air gap or dielectric. Therefore, conventional CV or IV measurements may be performed in various embodiments.

[0130] Alternatively, the gap can be filled with deionized water since the refractive indices of water and SiO2 are close. This allows for boundary layer reflections without any adverse effects (or at least things that cannot be dealt with). Deionized (or cleanroom-grade) water can be useful for reducing Maintaining cleanliness around sensitive and chemically pure substrate wafers. It has lower conductivity than regular water.

[0131] FIG. 14B shows related structures with differences in the configuration of the carrier or gate holder 2938. Here, it is configured as a ring and etched in the center using MEMS technology. This is best achieved by leaving protruding material around the electrodes. In any case, due to the large open area through which the laser and SHG radiation must pass, It may be particularly desirable to fill the area with DI water as described above.

[0132] Regardless, in the overall structure of the electrodes 2910, 2920, each embodiment typically , will be stationary with respect to the excitation radiation of the material in use. , may be stored by a robotic arm or transport device (not shown).

[0133] As described above, electrical measurements, such as current measurements, are performed on the electrodes of various embodiments. However, for example, electrodes that are capacitively coupled to the sample are used. Non-contact methods of measuring current can also be used, such as by

[0134] For the systems and methods described herein, a specimen (e.g., a semiconductor wafer or For example, the systems and methods described herein can be used to characterize the The method can be used to detect defects or contaminants in a sample as described above. The system and method described herein are used to characterize specimens during semiconductor wafer manufacturing or production. Accordingly, the system and method may be adapted to The systems and methods described herein can be used along the semiconductor manufacturing / production The systems and methods described herein can be integrated into automated wafer processing lines. For example, the system can be integrated into a semiconductor manufacturing line with front-office processing capabilities. Equipment floors that accept wafer cassettes such as Feeder Unified Pods (FOUPs) These cassettes can be fitted with an EFEM. Each is processed by a human operator or by moving the cassette along a manufacturing / production line. They can be delivered to those machines by automated cassette handling robots that move them from process to process. Cut.

[0135] In various embodiments, the system comprises: once the cassette is mounted on the EFEM: The FOUP opens and the robot arm selects individual wafers from the FOUP and inserts them into the system. The light-tight process box and vial are transported through an automatically operating door. The chuck can be configured to accommodate a sample placed on it. It can be designed to complement and fit with the robot arm so that it can At some point during the process, the wafer can be held up to a scanner to identify the unique laser markings.

[0136] Therefore, systems configured to be integrated into semiconductor manufacturing / assembly lines: Automated wafer handling capability from FOUP or other types of cassettes to EFEM as above integration of the chuck and robot rod / arm, designed in a way that is compatible with robotic manipulation Automatic light-blocking door that opens and closes to allow for wafer loading / unloading and It may have software that signals the EFEM for wafer identification.

[0137] (Part III) 15A and 15B illustrate hardware suitable for use in the subject systems and methods. This is described in U.S. Provisional Application No. 61 / 9808, filed April 17, 2014. Details are given in Section I, "Pump and Probe Type SHG Measurements," of the specification of No. 60, "Wafer Measurement Technology." Other system and method options include U.S. Provisional Application No. 2014 / 0040994, filed April 17, 2014. Section II of the specification of No. 61 / 980860 entitled "Wafer Metrology" entitled "System for Measuring Charge Decay" and methods, for example, intermediate optics, optical delay lines, and optional This includes those related to electrode function.

[0138] As shown, the system 3000 includes a sample holder 3030 held by a vacuum chuck 3030. A primary or probe laser 301 directs a probe beam 3012 of electromagnetic radiation onto the substrate 3020. 15B, the chuck 3030 includes an x ​​and y stage, and, if necessary, position the sample position 3022 across the wafer relative to where the laser is aimed. The device may also include a rotary stage for positioning the device, or may be mounted on such a stage. The y-stage allows for multiple wafer surface positions or locations without moving other hardware. The rotation stage allows scanning of the location 3022. The influence of the crystalline structure on SHG, such as strain, associated defects or areas of concern in the material being evaluated Further optional features, aspects and / or chuck 30 30 applications are presented elsewhere in this application. Sample location 3022 may be one or The sample location 3022 may be a composite substrate that includes at least two layers. The sample location 3022 may include a plate. between semiconductor materials with different impurities; between semiconductors and oxides; This may include interfaces between semiconductors and dielectric materials, between semiconductors and metals, or between oxides and metals. can.

[0139] When using system 3000, a reflected beam of radiation 301 is directed towards detector 3040. 4 will contain the SHG signal. Detector 3040 may be a photomultiplier tube, a CCD camera, an Valanche detectors, photodiode detectors, streak cameras, and silicon detectors The system 3000 may also include one or more shutter-type devices. 3050. The type of shutter hardware used may include a The time frame for the sample to be ejected, dumped, or otherwise directed away from the sample location depends on the time frame. An electro-optical blocking device such as a Kers cell or Kerr cell is used to provide a very short blocking period ( The operating time is 10 -9 ~10 -12 You can get a time of about 1 second.

[0140] Longer shut-off time intervals (e.g., about 10 -5 For longer than 100 seconds, a mechanical shutter or Alternatively, a flywheel chopper type device may be used. However, electro-optical isolators are not suitable. The device would allow a wider range of substances to be tested according to the following method: Photons that can be discretely switched on and off over very short time intervals, typically on the order of picoseconds to microseconds. A counting system 3044 can be used to resolve the counting of time-dependent signals. For fast time frames, optical delay lines can be incorporated as described above.

[0141] System 3000 may include an additional electromagnetic radiation source 3060, also referred to as a pump source. In various embodiments, the radiation source 3060 emits a directional beam 3062. Lasers, or divergent or optically collimated pulses, shown as 306. In the case of a laser source, the beam 306 2 may be collinear with beam 3012 (e.g., by using additional mirrors or prisms, etc.). The output wavelength of the light source 3060 is approximately 80 nm to approximately 1000 nm. Shorter wavelengths in this range (e.g., less than about 450 nm) may be used. This allows for the generation of light using fewer photons and / or at lower peak intensities than at longer wavelengths. It is possible to drive the charge excitation.

[0142] For flash lamps, the energy per flash or the power consumed during the flash Levels may depend on substrate material. Total energy per flash 1J to 1 A flash lamp generating 0 kJ was used to generate a fully depleted silicon-on-insulator (F However, pulsed or constant UV light sources may also be used. The key factor in the properties and applications of the pump is the transfer of charge carriers to the induced Suitable flash lamp manufacturers include Hellm, USA. These include Company A and Hamamatsu Photonics Co., Ltd.

[0143] When using a laser as the light source 3060, the wavelength may be nanosecond, picosecond, or femtosecond. It can be either a continuous laser or a faster pulsed laser source, or even a continuous solid state laser. In various embodiments, the pump source is wavelength tunable. Commercially available options include Spectra-Physics' Velocity and Vo rtex Tunable Laser. Also available: tunable solid-state solutions. are available from LOTIS' LT-22xx series of solid-state lasers.

[0144] Whether provided as a laser or flash lamp, the pump source 3060 , may be selected to have a relatively high average power, which may be from about 10 mW to about 10 W. However, more typically, it ranges from about 100 mW to about 4 W, depending on the material under investigation (again, The consideration is to inject charge carriers into the interface of the material (e.g., the dielectric interface). The charge carrier mobility is guaranteed to be induced by the material. The average power of the source 3060 is selected to be below the optical damage threshold of the material. For example, if the investigation material includes silicon, the pump source 3060 may be configured to The average optical power can be selected to be 1-2 W so as not to exceed the threshold.

[0145] The Probe Laser 3010 can be used for nanosecond, picosecond, or femtosecond or faster lasers. It can be either a pulsed laser source or a laser source with the required peak power, wavelength, and reliability. Two commercially available laser options are doped fiber and titanium sapphire devices. Coherent's VITESSE and Spectra-Physics' MAI TAI Femtolasers and other manufacturers are examples of suitable titanium sapphire lasers. Also, other suitable Ti:sapphire devices may be fabricated. Suitable doped fiber lasers may be fabricated using Manufactured by IMRA, OneFive, and Toptica Photonics. Depending on the plate material and pump type, many manufacturers, including Hamamatsu, offer picosecond and / or Nanosecond lasers may also be an option. Laser 3010 provides a wavelength of about 100 nm to about 2 It operates at a peak power of approximately 10kW to 1GW in the wavelength range of 1000nm, but the power supply can be less than 150mW on average.

[0146] Any of a variety of other so-called "intermediate" optical components may be used in system 3000. For example, the system can generate light directly from the laser 3010 and / or the light source 3060. Dichroic reflective or refractive filters that selectively pass reflected radiation and coaxial SHG signals. Alternatively, a prism may be used to filter out the weaker SHG signal. However, the use of a prism The dichroic system described above is preferred because the method has been found to be very sensitive to misalignment. Other options include the use of a diffraction grating or pellicle beam splitter. A light beam 3080 for focusing and collimating / cylindrical structure optics may be provided. , a filter wheel 3090, a polarizer 3092, and / or a zoom lens 3094. The device or assembly can be used in a system and can also measure angles (or arcs). Rotational adjustment (with corresponding adjustment to the detector) and in-line optics are preferred. There are also cases where this is not possible.

[0147] The output from the detector 3040 and / or photon counting system 3044 is transmitted to the electronic device 30 48. The electronic device 3048 may be a computing device, a computer, a tablet, The electronic device 3048 may be a processor, a microcontroller, or an FPGA. processor, processing electronics, control electronics, processing / control electronics, or one or more The operating system includes an electronic device that can be configured to execute multiple software modules. In addition to running the operating system, the processor also runs web browsers, phone applications, application, email program, or any other software application The computer may be configured to run one or more software applications, including: The electronic device 3048 may implement the methods discussed herein in, for example, RAM, ROM, EEPROM, The present invention can be implemented by executing instructions contained on a machine-readable non-transitory storage medium, such as The electronic device 3048 may include a display and / or graphics for interacting with the user. The electronic device 3048 may include a network interface. It can communicate with one or more devices via a network interface. The source may be, for example, a wired Ethernet, Bluetooth, or wireless connection. The device may include a transmitter, receiver, and / or transceiver capable of communicating.

[0148] As for the other options, the SHG signal is weak compared to the reflected beam that generates it. It is desirable to improve the signal-to-noise ratio of SHG counting. Photon counting gate times are reduced due to the blocking and / or delay processes described herein As the number of noise reductions increases, improvements become even more important. The solution is to actively cool the photon counter, using a cooling agent such as liquid nitrogen or helium. This can be done using cryogenic fluid or solid state cooling using a Peltier device. Other areas of improvement include the use of Marx Bank Circuit (MBC) in conjunction with shutter speed. Additionally, the system 3000 may include in-line The production line elements preceding or following the system 3000 may include , epitaxial growth systems, lithography and / or deposition (CVD, PVD, Any of the above systems (puttering, etc.) may be included.

[0149] In either case, Figures 16A and 16B show the SHG system of interest. 1 provides a first set of diagrams of purpose-built chuck hardware that may be used. The chuck 3030 holds the wafer 3020 by vacuum or other means. 0 is conductive and connected to a power supply. Optionally, the capacitive coupling probe 3100 is also The power supply is computer controlled, or at least its output is connected to a power supply 3120. is coordinated by the computer for the timing reasons summarized above. 00 can be similarly controlled and / or monitored. It is connected to a power supply 3120. It will be controlled in the sense that it is part of a capacitive circuit connected by a voltmeter. and monitored along with the chuck 3030 to ensure that the voltage is induced as intended. It can be recognized.

[0150] The probe 3100 has a hole 3102 or port (e.g., 0.2 mm diameter) in its ring. Since the light beams 3012, 3014 (probe beam and reflected SHG beam) are included in the It passes unobstructed and is fixed relative to the optical components, preventing the surface of the device from being skimmed. The optical element moves or stays with the (re)positioned sample position when scanning. The bond (indicating a positive "+" charge) remains at the center of the sample device. It is placed close to the surface (for example, within about 1 mm to about 2 mm), but does not touch it. The probe 3100 is supported by a lever arm or other means as shown in FIG. 3104, or may comprise a larger disk or plate. That's fine.

[0151] In the example shown in cross section in FIG. 16B, the wafer 3020 or device surface (including silicon) , separated from the silicon bulk layer by SiO2. Therefore, an inductive bias to the device surface is required. Otherwise, the conductive chuck 30 30, electrically isolated (at least substantially) from the underlying silicon, or is separated.

[0152] 17A-17C show an electromagnetic chuck including an electric coil 3130 connected to a power supply 3120. 3030. In use, the wafer 3020 is placed on the chuck 3030 and secured thereto. An alternating current (AC) is applied to the coil 3130, which causes an AC magnetic field to pass through the wafer. The alternating magnetic field induces an electric potential across the wafer 3020, including its device surface. This electric field then enables the various modes of SHG investigation mentioned above, Alternatively, a DC current may be applied in parallel with the chuck 3130. oriented coil 3130 to generate a constant magnetic field across the chuck due to the other effects described above. It is also possible to create

[0153] FIG. 18A shows the AC voltage (V) profile applied to the substrate bulk layer over time. FIG. 18B shows an example of a device and a substrate bus on which the device is fabricated. Induced voltage between the layers (V i ) is a hypothetical response of the substrate. The semiconductor material may be a semiconductor wafer or a portion of a semiconductor material. The AC voltage (V O ) profile (square wave) is shown in Figure 1. 9B is the induced voltage between the device and the bulk layer (V i ) is shown in Fig. 18. In either the 19A or 19A, the voltage input may differ from that shown, potentially resulting in Note that it may be applied in steps, ramps, sine waves, or other forms.

[0154] 18A and 18B, more specifically, to minimize noise and minimize the potential across the interface, Multiple photon counting windows to obtain statistically valid SHG intensity as a function of pressure For such purposes, it may be desirable to, for example, The timing is adjusted so that the voltage between the bulk and device layer is the same as voltage A at both points. For example, the voltage B at points B1 and B2, the voltage C at points C1 and C2, For example, if you use voltage A to record SHG and the count value at point A1 is , the count value at point A2 and points A3, A4, A n ...and the desired measurement time. The total number of counts measured during this period is then added up over a period of one second. The way to find the average count per gate is to divide it by the time spanned by this "gate". The SHG intensity can then be plotted as a function of bulk-device voltage. , points B1 and B2, as well as B3, B4, B n ...and measure the voltage B at The counts measured during this period can then be taken as an arbitrarily long sequence depending on the desired measurement time. over the time spanned by this "gate" as a way to find the average count per second. This allows the SHG intensity to be plotted as a function of the bulk-device voltage. Similarly, using this method, points C1 and C2, as well as C3, C4, C n Electricity at... Measurements for pressure C can be taken in an arbitrarily long sequence depending on the desired measurement time. The total number of counts measured over a given period is used to find the average number of counts per second. This allows us to calculate the SHG intensity as a function of the bulk-device voltage. Further information on the use of SHG intensity as a function of bias voltage is available. More details can be found in the DC bias literature, e.g., "Measurements in Second Harmonic Generation" Charge traps in irradiated SOI wafers,” IEEE Transactions on on Nuclear Science, Vol.51, No.6, December 2004 ,and "Optical Probe of Silicon Integrated Circuits Using Electric-Field-Induced Second-Harmonic Generation," ,A Applied Physics Letters, 88, 114107, 2006 , etc., each of which is incorporated herein by reference in its entirety.

[0155] More specifically, with respect to Figures 19A and 19B, these figures show silicon-on-insulator An example is shown here investigating a silicon-on-insulator (SOI) device. In this example, the conductive chuck is Starting in the "isolated" ground state, the bulk and device layers are at equilibrium potential. When the voltage applied to the block is suddenly changed, the voltage is applied to the conductive bulk layer of the sample. The device layer of the sample is directly connected to the conductors and separated from the bulk by a thin buried oxide layer. Because there is no electrical connection, a potential field or voltage will be induced between the device and the bulk layer. Between times "A" and "B", the voltage applied to the chuck remains unchanged. Because the dielectric between the device layers is imperfect, the induced potential drives leakage currents between the layers, The potential between the bulk layer and the device layer is then returned to its natural state. The decay can be monitored via SHG to provide insight into leakage current. At time "B," the voltage applied to the chuck is returned to ground potential, and the voltages at both ends of the interface are reversed. do.

[0156] For the systems and methods described herein, a specimen (e.g., a semiconductor wafer or For example, the systems and methods described herein can be used to characterize the The method can be used to detect defects or contaminants in a sample as described above. The system and method described herein are used to characterize specimens during semiconductor wafer manufacturing or production. Accordingly, the system and method may be adapted to The systems and methods described herein can be used along the semiconductor manufacturing / production The systems and methods described herein can be integrated into automated wafer processing lines. For example, the system can be integrated into a semiconductor manufacturing line with front-office processing capabilities. Equipment floors that accept wafer cassettes such as Feeder Unified Pods (FOUPs) These cassettes can be fitted with an EFEM. Each is processed by a human operator or by moving the cassette along a manufacturing / production line. They can be delivered to those machines by automated cassette handling robots that move them from process to process. Cut.

[0157] In various embodiments, the system comprises: once the cassette is mounted on the EFEM: The FOUP opens and the robot arm selects individual wafers from the FOUP and inserts them into the system. The light-tight process box and vial are transported through an automatically operating door. The chuck can be configured to accommodate a sample placed on it. It can be designed to complement and fit with the robot arm so that it can At some point during the process, the wafer can be held up to a scanner to identify the unique laser markings.

[0158] Therefore, systems configured to be integrated into semiconductor manufacturing / assembly lines: Automated wafer handling capability from FOUP or other types of cassettes to EFEM as above integration of the chuck and robot rod / arm, designed in a way that is compatible with robotic manipulation Automatic light-blocking door that opens and closes to allow for wafer loading / unloading and It may have software that signals the EFEM for wafer identification.

[0159] (Efficient collection of multiple polarizations) Different polarization components of the second harmonic generation signal provide information about different material properties. For example, silicon-based materials or crystals that have the same symmetry as silicon can be used. The second harmonic generation signal of p-polarized light can be sensitive to electrical properties. The optical second harmonic generation signal can provide strain or crystal-related information. A system that can control which polarization component or components are collected is It can be useful in isolating and collecting data on specific characteristics of the Various implementations of systems for collecting different polarization components of second harmonic generation signals are presented in this paper. This will be explained in the specification.

[0160] FIG. 20 shows a system capable of collecting second harmonic generation signals of a particular polarization. In particular, FIG. 20 shows a component that may be used to interrogate a sample such as a wafer. As shown, a system 4000 for inspecting a wafer 4120 is shown. The optical system includes a light source 4110, a polarizing optic (e.g., a polarizer) 4112, and a focusing optic (e.g., a focusing a focusing lens) 4114, a rotation stage 4116, a translation stage 4118, and a collection optics (e.g. 4124, polarizing optics (e.g., polarizing filter optics or polarizing The illustrated configuration may include a spectral filter 4122, a spectral filter 4126, and a detector 4130. 4110, a light source 4110, a polarizing optics (e.g., a polarizer) 4112, a focusing optics (e.g., a focusing A bundle lens 4114 is in the first optical path to direct the light to a sample (e.g., a wafer), Collection optics (e.g., collimation optics) 4124, polarization optics (e.g., polarization filters The optical system (or polarizer) 4122, the spectral filter 4126, and the detector 4130 There is a second optical path for light reflected from the

[0161] When using the system 4000, the light source 4110 can emit input light 4132. The light source 4110 may include a laser light source or other electromagnetic radiation source. The source 4110 may be a pulsed laser, such as a nanosecond, picosecond, or femtosecond laser, or a continuous laser. In various embodiments, the laser includes a solid-state laser. In the present specification, the light source 4110 may be a lamp that emits divergent or optically collimated light. The light source 4110 can emit light 4132 having any wavelength. For example, the light source 4110 emits light (41 32) can be emitted.

[0162] The system 4000 can direct polarized light to the sample. The source 4110 may output polarized light, such as linearly polarized light. , the system can polarize the input light 4132 using polarization optics 4112 . The polarization optics 4112 may include, for example, a polarizer that changes the polarization state of the input light 4132. In some embodiments, the polarization optics 4112 may be configured to For example, the polarization optics may include any suitable type of polarizer for modifying the , an absorptive polarizer that can linearly polarize the input light 4132. In some embodiments, the polarization optics 4112 may include a polarization optic configured to change the polarization state. A light control optical system may be provided, for example, to change the orientation of linearly polarized light (e.g., from vertically polarized light to horizontally polarized light). In some embodiments, for example, the polarization optics 4112 changes the light beam to a flat polarized light. For example, a polarized optical system provides linearly polarized light with a specific angle θ1 to the incident light. 4112 is a wafer 4120, and the direction of linear polarization θ1 of the input light 4132 is For example, the change can be made to a certain area of ​​the wafer 4120 or to a certain pattern on the wafer 4120. For example, the polarization optics 4112 generates s-polarized light for a certain pattern on the wafer 4120. In various embodiments, one or more hardware processors may be configured to process the input light 4 The polarization optics 4112 can be controlled to change the polarization state of 132 .

[0163] The system 4000 may focus the input light 4132 with focusing optics 4114 . The focusing optics 4114 focuses the input light 4132 onto an area 4136 on the wafer 4120. For example, focusing optics 4114 may include focusing optics for focusing an input One or more lenses capable of focusing light 4132 toward area 4136 of wafer 4120. may be included.

[0164] The system may also include collection optics to collect light reflected from the sample. The optical system may include, for example, one or more lenses positioned to receive the SHG light from the sample. The lens may include a lens or mirror.

[0165] In one implementation, the collection optics 4124 includes collimating optics that collect the SHG light from the sample. The collimating optics 4124 includes an output light 4134 received from the wafer 4120. Any suitable collimating optics for collimating the light may be included. The optical system 4124 may include one or more collimating lenses, such as one or more collimating lenses. Such one or more collimating lenses may be included, for example, If the focal length f is 1, the sample can be positioned at a distance corresponding to the focal length f. Other configurations are possible.

[0166] As mentioned above, information about different material properties is obtained from different polarization components of the second harmonic generation signal. , so that the system 4000 can select different polarizations of the SHG signal for detection. The system 4000 may be configured to emit light of a particular type, e.g., having a particular polarization state. Light with certain polarization characteristics is directed to detector 4130 using polarization optics 4122. The polarization optics 4122 can, for example, select a particular polarization state of the output light 4134. The polarization optics 4122 includes a polarizing filter or polarizer configured to pass light through the polarizing filter or polarizer. The polarization optics 4122 may include any suitable type of polarizer. The light source may include an absorptive polarizer that can selectively transmit linearly polarized light of a specific direction. For example, the control electronics, which may include one or more hardware processors, , controlling the polarization optics 4122 to change the polarization state selected from the output light 4134. For example, the polarizer can be configured to select linearly polarized light having a specific polarization angle θ2. In some embodiments, the control electronics may be configured to rotate, e.g. For example, by rotating the polarizer 4122, the light can be selected, for example, selectively transmitted. The control electronics may be configured to change the angle of the linear polarization. In this state, s-polarized SHG light reaches the detector in comparison with p-polarized SHG light from the sample. , selectively accepts s-polarized SHG light from the sample, and in the second state, Compared with the conventional method, the p-polarized SHG light from the sample is selectively transmitted to the detector. For example, the control electronics can control the polarization optics 4122 to allow Regarding the polarization optical system 4122, for example, in order to transmit s-polarized SHG light from the sample, In the first state, s-polarized SHG light from the sample is incident on the detector, and negligible SHG light from the sample is incident on the detector. It is possible to control the amount of p-polarized SHG light so that it does not enter the detector. The control electronics is configured to control the polarization optical system 4122, for example, to transmit p-polarized SHG light from the sample. In the second state, the p-polarized SHG light from the sample is incident on the detector, and the Therefore, it is possible to control the incident light so that a non-negligible amount of s-polarized SHG light does not enter the detector.

[0167] System 4000 may include any other optical elements. For example, system 4000 may include The optical system may include a spectral filter 4126 for selecting specific wavelengths of light. The 4126 can be a bandpass, highpass, or lowpass filter. The filter 4126 may, for example, selectively filter out light having a particular wavelength or range of wavelengths. It may be transmitted to

[0168] As described above, the system 4000 may include a detector 4130. The detector may be a photoelectric electron multipliers, avalanche detectors, photodiode detectors, streak cameras, and The detector 4130 may include an SHG signal. The output light 4134 may be detected.

[0169] For wafer 4120, a specimen stage, which in some embodiments may include a chuck 4140 may be used to hold the specimen in place. In some designs, the wafer 4120 can be positioned and moved within the plane of the wafer. The stage may include a translation stage 4118 and / or a rotation stage 4116 that can The rotation stage 4116 rotates the wafer about the axis 4128 relative to the wafer area 4136. A translation stage may be able to rotate 4120. The position of the rotation stage 4116 and translation stage 4118 can be changed. , for example, by control electronics, which may include one or more hardware processors. There may be cases where it is controlled.

[0170] As described above, the system detects an SHG signal having a first polarization, e.g., s-polarization. to obtain a first type of information about the sample, and to obtain a second type of SH having a second polarization, e.g., p-polarized light. The G signal can be detected to obtain a second type of information about the sample. For example, first collect the first polarization component, then collect the second polarization component. Other embodiments described herein may be configured to use multiple biases. Light components, e.g., light of a first polarization (e.g., s-polarized light) and light of a second polarization (e.g., p-polarized light) and configured to simultaneously direct light from the first and second detectors, respectively. .

[0171] Figure 21 shows an example of a system such as that described in Figure 20. The system includes polarization optics. Polarizing beam splitter 5122 replaces system 4122. First and second detectors 5130 instead of a single detector 4130 arranged to receive A polarizing beam splitter receives light and splits it into first and second In the system shown in Figure 21, the beam splitter is receiving second harmonic generated light from the sample and dividing the light into first and second (e.g., orthogonal) polarization components; Polarizing beam splitters are positioned to split the light into two components (e.g., s-polarized and p-polarized light). The detector directs the first and second polarization components along separate first and second paths, respectively. , and direct them to the first and second detectors. This results in the first and second second harmonic generation signals Data on the polarization components can be collected simultaneously.

[0172] In some embodiments, the sample can be scanned or the sample can be illuminated from the light source 4110. The beam 4132 directed onto the sample is scanned to obtain the SHG signals for different parts of the sample. The signal can be acquired to generate an SHG image of the sample or part of it. Other techniques can be used to form images from second harmonic generated light from a sample, such as Advantageously, in the system shown in FIG. 21, the first and second polarizations of the SHG signal are Orthogonal components, such as p- and s-polarized components, can be collected separately and measured simultaneously. Polarized light can be collected simultaneously from a single scan of the sample. When signals with different optical states are collected simultaneously to evaluate a substance, the throughput can be increased by, for example, two times. As mentioned above, silicon-based or silicon-identical materials can be used. For crystals with symmetry, the p-polarized SHG signal component is related to electrical properties such as interfacial electrical properties. The s-polarized SHG signal component can provide information about the strain or crystal-related information. The system disclosure herein can be used to synchronize such information. can be collected at the same time, thereby increasing throughput and / or processing speed. While maintaining the same level of accuracy, the two polarization components provide a more comprehensive characterization of the material. Signal normalization may also be provided for multiple polarization components.

[0173] Polarizing beam splitters consist of a polarizing beam splitter cube, a polarizing selective reflective coating on the surface, Other types of polarizers may also be used. The other components in the system are the same as those shown in Figure 20. Similarly, various features and operations described in FIG. 20 or elsewhere throughout this disclosure may be The above and operating modes are applicable to the system shown in FIG. 21, but a wide range of variations are possible. For example, first and second detectors 51 receiving the first and second polarization components are also possible. Instead of having a detector array (e.g., a CCD detector array) For example, the detector array may include a plurality of pixels. Different regions of the detector array, e.g., first and second regions of the detector array, may be included. The detector array can receive the first and second polarization components, respectively. A region may comprise one or more pixels of the detector array. Still other variations are possible. be.

[0174] (SHG imaging) As mentioned above, second harmonic generation provides non-destructive, sensitive information on critical interfacial electrical properties. However, various point-based measurement / sampling techniques are widely for spatial profiling of large areas with high coverage and resolution. Therefore, in various embodiments disclosed herein, SHG imaging These imaging systems provide designs for image-based inspection systems that provide better image capture of specimens. It can provide SHG images or distribution maps of SHG signals over large areas, These imaging systems can also provide high resolution. Expanding the existing applicability of second harmonic generation to larger areas with improved throughput This can extend coverage of randomly distributed defects / issues. Such an SHG imaging system may include one or more beam splitters for generating multiple beams. a beam splitter, and multiple SHG signals for capturing multiple signals over an area of ​​the sample. The detector can be used to form an SHG image. Also, using scanning techniques In some cases, the SHG imaging system can also use imaging optics to capture the sample or or imaging a region of the sample and / or detecting an SHG signal associated with the region of the sample. The SHG image may be formed by projecting the image onto a detector array. An example of such a system is described below. Reveal.

[0175] For example, FIG. 22A shows a laser beam 7126 split into multiple beams 7122A, 7122B, 712C, 712D, 712E, 712F, 712G, 712H ... 2B, 7122C. In some embodiments, the plurality of beams 7122A, 7122B, 7122C may be Scans over an area of ​​the sample 4120 to provide an SHG image of the sample or part of it It is possible.

[0176] As with the other SHG systems described herein, the system 8000 shown in FIG. A second height is directed to the sample 4120 supported on the sample stage 4140. a light source (e.g., a laser light source) configured to output light 7126 capable of generating harmonic generation; ) 7108. As with the other systems described herein, the sample stage 41 40 may include a translation stage, such as an xy translation stage 4118, and / or a rotation stage. It may contain 4116.

[0177] The system 8000 shown in FIG. 22A receives a beam and splits it into multiple beams. The beam splitter 7110 may be configured to split or separate the beams. The beam splitter 7110 can also be used as a multi-spot beam generator or an array beam generator. The multiple beams may be a linear array of beams or a two-dimensional array of beams. Beam splitter 7110 is configured to diffract light from one beam into multiple beams. The optical element may comprise a diffractive beam splitter such as a diffraction grating or a diffractive optical element. In some embodiments, the beam splitter 7110 may comprise an acousto-optic modulator. An acousto-optic modulator can, for example, modulate a single input beam to produce multiple output beams. The system 80 shown in FIG. 22A can be configured to diffract light from the force beam. In FIG. 1, a beam splitter 7110 splits a beam 71 output from a laser light source 7110. 26 and generates multiple beams 7122A, 7122B, and 7122C. Although the system shown here is a 3D laser beam splitter, more or fewer beams may be generated by the beam splitter. The number of beams 7122A, 7122B, 7122C (and the number of beams that can be irradiated by the beams) The number of SHG signals obtained (the corresponding points or positions on the sample that are obtained) can be calculated as follows: May be greater than 5, 10, 15, 20, 25, 30, or any value between these Any range may be used. More or fewer beams 71 may be used on the sample 4120. 22A, 7122B, 7122C, the illumination spot or position, and / or the SHG signal Numbers are also possible.

[0178] The system 8000 includes a plurality of beams 71 generated by a beam splitter 7110. and a scanner 7112 configured to receive 7122A, 7122B, and 7122C. The scanner 7112 may include, for example, one or more mirrors or reflective surfaces. and tilt, rotate, and / or change the direction of the received light and refocus it in a different direction. Other types of scanners or beam scanners may also be used. The scanner 7112 scans the beam 712 over one or more regions of the sample 4120. 2A, 7122B, and 7122C can be configured to scan.

[0179] System 8000 includes an objective lens positioned between beam splitter 7110 and the sample. 7116, which is configured to focus a plurality of beams 7122A, 7122B, 7122C, and then beams 7120A, 7120B, 7120C shown in FIG. 22A. In some embodiments, the objective lens 7116 is A plurality of beams 7120A, 7120B, and 7120C are focused onto the substrate 4120. In the system shown in A, the scanner 7112 is connected to the beam splitter 7110 and the objective lens. Since the objective lens 7116 is located in the optical path between the objective lens 7116 and the beams 7122A, 7122B, 712C, 712D, 712E, 712F, 712G, 712H, 712I, 712J, 712K ... 2B, 7122C are scanned. Similarly, multiple beams incident on the sample 4120 7120A, 7120B, and 7120C are also affected by the objective lens 7116 (e.g., focusing). After the sample is scanned over at least a portion of the sample, In some implementations, the objective lens 7116 is aligned along a path that is more perpendicular to the sample 4120. Thus, multiple beams 7120A, 7120B, 7120C can be directed at the sample.

[0180] The multiple beams 7120A, 7120B, and 7120C incident on the sample 4120 are These separate SHG signals are then fed to the objective lens 7116. In some implementations, such as that shown in FIG. 22A, the multiple SHG signals are It travels along a path that is substantially perpendicular to the sample 4120 toward the objective lens 7116 .

[0181] The system 8000 shown in FIG. 22A further includes a dichroic mirror or reflector 7114. The dichroic mirror 7114 splits the multiple beams 7122A, 7122B, 7122C (and and 7120A, 7120B, 7120C) The dichroic mirror 7114 may be arranged to reflect the objective lens 7116 and the scanning lens. The beam splitter 7110 and the SHG signal from the and the scanner 7112. The dichroic mirror 7114 Therefore, the SHG signal can be generated by reflecting light having a wavelength of 1000 .mu.m. The signal is reflected by dichroic mirror 7114.

[0182] The dichroic mirror 7114 directs the multiple beams 7122A, 7122B, 7122C toward the source 7 108 and the beam splitter 7110. For example, Dichroic mirror 7114 corresponds to multiple beams 7122A, 7122B, 7122C. It may be configured to transmit a wavelength of light (for example, a fundamental frequency). By inserting a dichroic mirror 7114 in the optical path between the light source 7108 and the sample 4120, 712A, 712B, and 712C from the laser light source and beam splitter 7110. 2B, 7122C and incident on the sample 4120. For 7122A, 7122B, 7122C (and 7120A, 7120B, 7120C) Each of the multiple SHG signals thus generated is reflected from the dichroic mirror 7114. The wavelength may be suitable for

[0183] The system 8000 shown in FIG. 22A includes multiple SHG signals arranged to receive the multiple SHG signals. Detectors 8130A, 8130B, 8130C (e.g., photomultiplier tubes or PMTs) In particular, in the illustrated system 8000, the dichroic mirror 7114 includes a plurality of SH The G signal is fed to multiple detectors 8130A, 8130B, and 8130C via optical paths 8128A and 8128 These optical paths 8128A, 8128B, and 8128C are configured to reflect the light along these optical paths 8128A, 8128C. 8B, 8128C are shown in FIG. 22A as being curved, but these paths are For example, the paths 8128A, 8128B may be different and may be linear and close to each other. 8B, 8128C may also be changed by optical elements such as mirrors or optical fibers. or other optical components such as fiber devices or integrated optics or waveguide devices. As described above, the dichroic mirror 7114 may be configured to receive the SHG signal from the dichroic mirror 7114. The optical filter may be configured to reflect wavelengths of light of the SHG signal so as to be reflected from the optical filter. In addition, multiple detectors 8130A, 8130B, and 8130C are arranged opposite the dichroic mirror 7114. and may be arranged in the optical path to receive the respective SHG signals.

[0184] The system 8000 shown in FIG. 22A includes three optical detectors 8130A, 8130B, Although the 8130C is shown, more or fewer optical detectors may be used. The number of detectors 8130A, 8130B, 8130C (and the corresponding number of SHG signals) is For example, 3, 5, 10, 15, 20, 25, 30, or any value between these. The optical detectors 8130A, 8130 may be more or less B, 8130C and / or SHG signals are also possible. As explained below, some In some embodiments, one detector array (or more than one detector array) may be designated detector 8130A. , 8130B, 8130C can be used.

[0185] Such a system 8000 includes multiple detectors 8130A, 8130B, and 8130C. can be used to advantageously provide SHG data for multiple points or locations, thereby In addition, multiple positions can be scanned to obtain a partial image of the sample. For example, multiple beams 7122A, 7122B can be used to obtain SHG signals. B, 7122C can extend in a first direction, for example, the x (or y) direction. These beams 7122A, 7122B, 7122C are then directed in a second (possibly orthogonal) direction For example, scanning in the y (or x) direction to obtain the SHG signal over an area of ​​the sample 4120 Additionally or alternatively, the sample 4120 can be sampled. To provide a further scan of the entire investigation area, the light source 7108 and the objective lens 71 16. In some embodiments, for example, the scanner 7112 can be Scan multiple beams 7122A, 7122B, and 7122C in the x-dimension, for example, and The sample stage 4140 may scan or otherwise move the sample in another direction or dimension, e.g., y. In this way, an SHG image over an area on the sample 4120 can be obtained. A map of the SHG signal distribution can be obtained using multiple detectors 8130A, 8130B, Having an 8130C can advantageously increase the efficiency or speed of data collection. do.

[0186] Therefore, in various embodiments having a system such as that shown in FIG. 22A, a laser light source The light (and SHG signal) from the laser is split into multiple beams. The S generated by different beams of incident light can be scanned in parallel over an area. The HG signal is detected by a different channel (e.g., a photomultiplier tube or PMT channel). The final image can be generated from a combination of data from an array or multiple PMT detectors. Therefore, the multi-beam scanning device can be configured to receive beams from multiple channels. By using simultaneously acquired signals, fast scan speeds can be achieved. Cut.

[0187] Thus, in various embodiments, either the laser beam or the wafer (or both) Rapid scanning of the SHG signal over one or more regions of the sample is used. Two-dimensional imaging of SHG from different positions (e.g., x, y positions) can be formed. A point-to-point mapping of the signal can be generated, which allows for the identification of objects associated with the SHG signal. It can provide spatial distribution of physical parameters (e.g., charge density, strain, interface states, etc.). can.

[0188] A wide range of variations are possible, e.g., one light source, one beam splitter, one switch Instead of a scanner, one dichroic mirror and one objective lens, any of these components may be used. One or more of the components may be included in the system 8000, and these components may be different. For example, as shown in FIG. 22B, the SHG signal received from the objective lens may be A dichroic mirror is provided between the objective lens 7116 and the scanner 7112 so that the A reflecting mirror 7114 may be placed. In addition, an optical fiber or an integrated optical component (e.g., Waveguide-based components) can be used in the SHG investigation system 8000, and , instead of multiple detectors 8130A, 8130B, 8130C, one or more detector arrays ( For example, different regions of the detector array may be used to measure the The beams 7122A, 7122B, and 7122C incident on the material 4120 produce In some embodiments, the incident beam can be used to collect the different SHG signals generated. The SHG signal for a specific one of the 7122A, 7122B, and 7122C is detected. The integrals over the respective regions on the detector array can be obtained. Any of the components, features, and / or methods or techniques disclosed herein may be used. For example, one or more polarizing beam splitters can be used to separate the s-polarized and p-polarized components. Light of first and second polarization states, such as polarization components, can be collected simultaneously. For example, , see FIG. 21 and related discussion.

[0189] FIG. 23 illustrates another system 1000 for generating an SHG image of an area of ​​a sample 4120. This SHG imaging system 10000 images the sample 4120 or a region thereof. Image and / or project SHG signals associated with a region of the sample onto a detector array 10116. An imaging optical system 10114 is used to form an SHG image.

[0190] As with the other SHG systems described herein, the system 10000 shown in FIG. is used to generate second harmonic generation from a sample 4120 supported on a sample stage 4140. a light source (e.g., a laser) configured to output light that can be directed toward the sample 4120 for As with the other systems described herein, the sample stage 4140 is a translation stage, such as an xy translation stage, and / or a rotation stage 41 It can contain 16.

[0191] The system 10000 shown in FIG. 23 further includes optional focusing optics 10112. , focuses light from the light source 10110 to one position on the sample 4120. The focusing optics For example, some embodiments may include one or more lenses or mirrors. can.

[0192] The system 10000 shown in FIG. 23 also provides a second harmonic generation (SHG) beam from the sample 4120. The projection optical system 10112 includes a projection optical system 10112 configured to collect such light. For example, in some embodiments, the optical element may include one or more lenses or mirrors. This can be done.

[0193] The system 10000 shown in FIG. 23 is configured to receive second harmonic generated light from a sample 4120. The detector array or pixelated detector 10116 is , including a plurality of detectors or pixels, and processing the electrical signals generated by the pixels of the detector array. This allows the formation of an image or map of the intensity levels of the light signals received by the pixels. The detector array 10116 may be, for example, a charge-coupled detector (C The detector array may be a CD (Cell-Diode) array, but other types of detector arrays may also be used. The detector array 10116 may, in one embodiment, comprise a device based on time-dependent integration. Integrating the signal over time can provide an increase in signal measurement.

[0194] In some embodiments, the projection optics 10114 may include one or more optical intensities The imaging optics 10114 may include, for example, one or more optical elements. including multiple lenses, one or more mirrors, or a combination thereof In some embodiments, for example, the detector array 10116 may be arranged to focus on a conjugate plane ( For example, the image plane (or the corresponding object plane). In some embodiments, the sample 4120 (or the SHG light emanating from different locations on the sample) The SHG light is focused onto the detector array 10116. The laser beam is generated by irradiating the sample with laser light. It can extend over an area or a point area.

[0195] Thus, in various embodiments, the SHG signals from different locations on the sample 4120 are are mapped to different positions on the detector array 10116. SHG signals at different positions are generated by the light from the laser light source 10110 incident at different positions. , and thus the detector array 10116 can detect different The SHG signal at each position is measured to generate an image or map of the distribution of the SHG signal on the sample. This can be done.

[0196] In some embodiments, the sample is is translated relative to the laser light source and the projection optical system. (and detector) can be translated relative to the sample to image a larger area of ​​the sample. Additionally, time integration can be used to increase the measured signal level. It is also possible.

[0197] Thus, in various embodiments, the laser beam remains stationary and the sample (e.g., , wafer) is translated while the SHG signal is projected onto a pixelated detector. The time-dependent integral is In some implementations, this may be employed to increase the signal level being measured. These different pixel elements are spatially spaced on the wafer surface paired with corresponding pixels on the detector array. The local SHG signal from the position can be recorded.

[0198] A wide range of variations are possible, for example, one light source 10110, one detector array 101 16, instead of a set of focusing optics 10112 or a set of projection optics 10114, Any one or more of these components may be included in the system 8000. Any of the components, features, and / or methods or techniques disclosed herein may be used. For example, one or more polarizing beam splitters can be used to separate the s-polarized and p-polarized components. Light of first and second polarization states, such as polarization components, can be collected simultaneously. For example, , see FIG. 21 and related discussion.

[0199] (Variation) Embodiments of the present invention have been described above, along with details regarding feature selection. For further details, these may be found in connection with the above-referenced patents and publications. These techniques are not only well known but are also generally known or appreciated by those skilled in the art. Regarding the method-based aspects, the same shall apply to additional operations that are generally or logically used. The same may apply to such methods, including methods of manufacture and use. , for these, any sequence of logically possible events, as well as the sequence of events listed Furthermore, when providing a range of values, all intervening values, i.e. The upper and lower limits of a range, and any other stated or intervening value in that stated range, are expressly incorporated herein by reference. It will be understood that the invention is encompassed by any of the alternatives of the variations of the invention described. The features may be used independently or in combination with any one or more of the features described herein. Together, we aim to clarify and assert.

[0200] As used herein, a phrase referring to "at least one of" a list of items refers to a single item. refers to any combination of those items, including "a," "b," or "c." "At least one" is intended to include a, b, c, ab, ac, bc, and abc.

[0201] Some examples of embodiments of the present invention incorporating various features as needed. Although described with reference to each of these, it is understood that such modifications are intended to be included. Any embodiment of such invention described is not limited to that described or shown. Modifications may be made to the above and equivalents (as described herein or included for brevity) may be incorporated. (whether included or not) without departing from the true spirit and scope of this specification. Certain features that are described in this specification in the context of separate implementations may also be used interchangeably. Conversely, the implementation described in the context of a single implementation may be combined and implemented in a single implementation. Various features may also be implemented separately in multiple implementations or in any suitable subcombination. Furthermore, the features may be described above as acting in particular combinations. Even if the first claim is made in this way, one or more of the claimed combinations may be Numerical features can be extracted from the combination in some cases, and the claimed combination The combination can be directed to a subcombination or a variation thereof.

[0202] The various processing examples described may be implemented using a general-purpose processor, a digital signal processor (DSP), or , Application Specific Integrated Circuits (ASIC), Field Programmable Gate Arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic, discrete hardware hardware components, or any of them designed to perform the functions described herein. A general purpose processor may be implemented or performed using a combination of a microprocessor, a Alternatively, the processor may be any conventional processor, computer, or the like. It may be a controller, microcontroller, or state machine, and the user interface A user interface port that communicates with the interface and receives commands entered by the user. processor, operating under the control of the processor and communicating through the user interface port At least one memory (e.g., hard drive) that stores electrical information including programs. hard disk or other equivalent storage device, and random access memory), VGA, DVI, HD Through any kind of video output format such as MI®, DisplayPort, etc. It may be part of a computer system having a video output that generates the output.

[0203] Regarding processors, and also combinations of computing devices, e.g., DSPs and microprocessors, A combination of processors, multiple microprocessors, one or more in conjunction with a DSP core It may be implemented as multiple microprocessors, or any other such configuration. , these devices may be used to select values ​​for the devices described herein.

[0204] The steps of a method or algorithm described in connection with the embodiments disclosed herein ,directly in hardware, in software modules executed by a processor, and The software module can be implemented with a combination of these. RAM, flash memory, read-only memory (ROM), electrically programmable EEPROM, electrically erasable programmable ROM (EEPROM) OM), register, hard disk, removable disk, CD-ROM, or It may reside on any other form of storage medium known in the art. The processor can read information from the storage medium and write information to the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal. It can exist as.

[0205] In one or more example embodiments, the functions described may be implemented using hardware, software, It may be implemented in software, firmware, or any combination thereof. If so, the functions may be stored on, transmitted over, or transmitted to one or more computer-readable media. The computer outputs analytical / calculated data such as instructions, code, and other information. Readable media include any medium that facilitates transfer of a computer program from one place to another. This includes both computer storage media and communication media, including any media of any kind. It can be any available medium that is accessible by a computer. Such computer readable media include RAM, ROM, EEPROM, CD-ROM, ROM or other optical disk storage device, magnetic disk storage device or other magnetic storage device or carrying or storing desired program code in the form of instructions or data structures. Any computer that can be used to Other media may be included. Memory storage devices may also include rotating magnetic hard disk drives, optical Disk drives, or flash memory-based storage drives, or other The storage device may be a solid-state, magnetic or optical storage device such as

[0206] Also, any connection is properly termed a computer-readable medium. However, coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or using wireless technologies such as infrared, radio, and microwave to communicate with the website, Coaxial cable, fiber optic cable when transmitted from a server or other remote source Cable, twisted pair, DSL, or wireless such as infrared, radio, and microwave Technology is included in the definition of media. Disk and disk as used herein Discs include compact discs (CDs), laser discs, optical discs, digital Includes digital versatile discs (DVDs), floppy disks, and Blu-ray discs A disk usually reproduces data magnetically, and a disk is a The data is optically reproduced by a laser. Combinations of the above are also included within the scope of computer-readable media should be included in

[0207] The actions described herein may be performed on or via a website. A website can run on a server computer or, for example, on a client computer. It can be downloaded to your computer and run locally or on a server The website can be accessed via a mobile phone or PDA. The website can be accessed via the You can use any format of HTML code like MHTML or XML, Additionally, you can use any format, such as Cascading Style Sheets (CSS) or other formats. It can be used as such.

[0208] Additionally, the inventors believe that only claims using the word "means" are within the meaning of 35 U.S.C. 112, paragraph 6. Furthermore, from the specification: No limitation of any kind may be included in any claim unless it is expressly included in the claim. The computers described herein are not intended to be general purpose computers. computer, or a special purpose computer such as a workstation. The program may be written in C, or JAVA, BREW, or any other The program can be written in a programming language such as or optical, e.g. computer hard drive, memory stick or SD On removable disks or media such as media or other removable media The program may also be executed over a network, e.g. , a server or other machine can send a signal to the local machine to The thin may be caused to perform the operations described herein.

[0209] Also, all features, elements, and structures described with respect to any embodiment provided herein. The components, features, acts and steps may be freely combined with those from any other embodiment. Please also note that these are intended to be combinable and interchangeable. Any feature, element, component, function, or step is described with respect to one embodiment only. Where applicable, the feature, element, component, function, or step is referred to in this specification unless expressly stated otherwise. It should be understood that the present invention may be used in conjunction with any of the other embodiments described herein. Therefore, this paragraph, in certain instances, may, by the following explanation, or substitution is permitted at any time, even if it is not explicitly stated that a different embodiment is possible. combine features, elements, components, functions, and operations or steps from the , features, elements, components, functions, and operations or steps from one embodiment may be combined with other embodiments. as a pre-emptive basis and written support for introducing claims, replacing those in the form Representing an enumeration of all possible combinations and permutations is particularly useful for It is to be understood that the permissible combinations and substitutions can be readily recognized by those skilled in the art. This would clearly be an excessive burden.

[0210] In some instances, entities may be referred to herein as being combined with other entities. "Interdigitation," "coupling," or "connection" (or any of these forms) The terms "entity" and "entity" are sometimes used interchangeably herein, and the two entities Direct coupling of the entity (non-negligible, no intervening, e.g., parasitic entities) ) and indirect coupling of two entities (non-negligible, one or more, parasitic It should be understood that this encompasses any direct interaction between entities (with or without an intervening entity). are shown as being joined or are interchangeable without mentioning any intervening entities. When listed as being combined, these entities may be used where the context requires otherwise. It should be understood that unless expressly indicated otherwise, they may be indirectly coupled to one another.

[0211] Reference to a singular item includes the possibility that there are plural of the same items. As used in this specification and the appended claims, the singular "one" is used. "a," ​​"an," "said," and "the" are used interchangeably unless otherwise specified. In other words, the use of the article As with the scope of the claim, "at least one" of the objects in the above description is possible.

[0212] Furthermore, any optional element (e.g., "usually," "possibly" or "possibly" as used herein) may be omitted from the claims. "may," "could," "may," "may," etc. Please note that it may be created excluding elements specified by the description used. Therefore, this statement should not be construed as a substitute for exclusionary terms such as "solely" or "solely" in connection with the recitation of claims. Precedent for using other terms or other "negative" claim limitation language It is intended to serve as a foundation. Without using such exclusive terms, The term "comprising" in a claim means that a given number of elements are included in the claim. whether the addition of functionality changes the nature of the claimed elements This allows for the inclusion of any additional elements, regardless of whether they can be considered as such. Furthermore, any such term "comprises" in a claim may be replaced with the exclusive language "or Furthermore, unless specifically defined in this specification, All technical and scientific terms used herein must be interpreted in a manner that maintains the validity of the claims. However, the meaning should be given as widely and commonly understood by those skilled in the art whenever possible.

[0213] Although various modifications and alternative forms are possible for the embodiments, specific examples thereof are shown in the drawings. However, these embodiments may be modified in any way to suit the particular form disclosed. Rather, all modifications, equivalents, and equivalents falling within the spirit of this disclosure are intended to be included. It should be understood that the present invention covers all alternatives and equivalents. Any feature, function, act, step, or element recited within the scope of a claim may not be included in the patent claim. The invention may be modified by features, functions, steps, or elements not within the scope of the invention. Any negative limitations (as set forth above or otherwise) in the claims defining the scope of the invention are hereby incorporated by reference. The same applies to variations or embodiments of the present invention. The present invention is not limited to the embodiments described herein, but is limited only by the scope of the following claims. Therefore, the inventors claim as follows:

Claims

1. 1. A system for characterizing a sample using second harmonic generation, comprising: a sample holder configured to support a sample; a light source configured to direct a light beam at the sample to generate a second harmonic generation (SHG) signal from the sample; an array beam generator configured to generate a two-dimensional array beam using the light beam received from the light source; a scanner disposed in an optical path between the array beam generator and the sample, the scanner configured to scan the two-dimensional array beam received from the array beam generator across the sample; an optical detection system including at least one detector array configured to receive an SHG signal generated by the two-dimensional array beam from the sample and generate a signal indicative of the detection of the SHG signal; a polarizing beam splitter configured to separate the received SHG signal into first and second polarization components and direct the first and second polarization components respectively to first and second detector arrays of the at least one detector array; an objective lens configured to focus the two-dimensional array of beams onto the sample and receive the SHG signal from the sample; and processing electronics configured to receive the signals from the at least one detector array and to use the received signals to generate a distribution map of the SHG signal over an area on the sample.

2. The system of claim 1 , wherein the at least one detector array comprises a two-dimensional array.

3. The system of claim 1 , wherein the at least one detector array comprises a CCD array.

4. The system of claim 1 , wherein the at least one detector array comprises a time-dependent integrator.

5. The system of claim 1 , wherein the objective lens is further configured to image the sample onto the at least one detector array.

6. The system of claim 1 , wherein the objective lens includes an imaging lens, and the at least one detector array is positioned at a conjugate image plane of the sample relative to the imaging lens.

7. The system of claim 1 , wherein the objective lens comprises a focusing lens configured to focus light from the light source onto the sample.

8. The system of claim 1 , further comprising a translation stage configured to translate the sample relative to the light source and the at least one detector array.

9. The system of claim 8 , wherein the translation stage comprises an xy translation stage.

10. The system of claim 1 , wherein the first and second polarization components are s-polarized and p-polarized, respectively.

11. The system of claim 1 , wherein the scanner comprises one or more mirrors or reflective surfaces.

12. The system of claim 1 , wherein the scanner is in an optical path between the array beam generator and the objective lens.

13. The system of claim 1 , wherein the array beam generator comprises an acousto-optic modulator.

14. The system of claim 1, further comprising a dichroic reflector configured to receive the SHG signal from the sample and direct the SHG signal to an optical detection system.

Images