Endpointing by induced desorption of gases and analysis of the re-covering

Abstract

This invention covers a method for use with a photomask, comprising the steps of: (a.) guiding a particle beam in gas particles to a photomask element; (b.) inducing desorption and / or adsorption of at least some gas particles in the element region; and (c.) capturing signals of secondary particles and / or backscattered particles and / or other free-space signals generated by the particle beam during the desorption and / or adsorption processes. The invention further relates to a corresponding apparatus for use with a photomask.

Description

[Technical Field]

[0001] The present invention relates to a method, apparatus and computer program for determining the material on a photomask through a particle beam and for repairing defects in the photomask. [Previous Technology]

[0002] Due to the increasing density of microelectronics, lithography masks (hereinafter commonly referred to as "masks") must image increasingly smaller structural elements onto the photoresist layer of the wafer. To meet these requirements, the exposure wavelength has been shifted to shorter wavelengths. Currently, argon fluoride (ArF) excimer lasers are mainly used for exposure, emitting light at a wavelength of 193 nm. Lithography systems using light sources emitting extreme ultraviolet (EUV) wavelengths (10 nm to 15 nm) and corresponding EUV masks are also used. By simultaneously developing various variations of conventional binary lithography masks, the resolution of wafer exposure processing has been improved. Examples include phase masks or phase-shifting masks and masks used for multiple exposures.

[0003] However, as the size of structural components continues to shrink, lithography masks cannot always be produced on wafers without any printable or visible defects. Due to the high cost of mask production, defective masks are repaired as much as possible.

[0004] There are two important defects in shadow masking: first, the dark defect, and second, the sharpness defect.

[0005] Dark defects are locations where adsorbent material and / or phase-shifting material are present, but such material should not be present. These defects are preferably repaired by removing excess material through localized etching.

[0006] In contrast, clear defects are defects on the photomask that have higher transmittance than an identical defect-free reference location when optically exposed in a wafer stepper or wafer scanner. In mask repair processes, these clear defects can be eliminated by depositing a material with appropriate optical properties. Ideally, the optical properties of the material used for repair should match those of the adsorbent or phase-shifting material.

[0007] One known method for removing dark defects is the use of electron beams directed directly onto the defects to be repaired (exposed). Due to the use of an electron beam, in particular, that electron beam may be precisely manipulated and positioned on the defect. Combined with a precursor gas (also referred to as a treatment gas), which can be present in the mask to be repaired or adsorbed on the mask itself, with the incident electron beam may induce a reaction similar to the local etching treatment. This induced localized etching treatment removes the (defective) excess material fraction from the mask, allowing the desirable adsorbent properties and / or phase shift properties of the microshadow mask to be generated or restored.

[0008] Alternatively, the precursor gas used may also be selected such that deposition treatment can be induced upon exposure to the electron beam. Therefore, additional material may be deposited on the clear defect to locally reduce the light transmittance of the mask and / or increase the phase shift properties.

[0009] The mask to be repaired may typically have a multilayer structure consisting of at least two materials, typically disposing one over the other. Herein, the upper material (material facing the electron beam) may be used as an adsorbent material, a phase-shifted material, or a material for the defect, while the lower material may be used as a substrate or carrier material for the microshape mask to be repaired (or as a material for some other elements arranged below the defect).

[0010] There may be backscattering of electrons or particles under the interaction of an electron beam or another particle beam used for etching or deposition with the material of the precursor gas or defect. For example, backscattered electrons can be detected simultaneously with etching and / or deposition treatments, which result in signals of backscattered electrons (e.g., EsB signal, EsB: energy-selective backscattering). In addition or in addition, secondary particles, such as electrons, may be generated by the interactive treatment of the particle beam with the precursor gas or defective material. For example, secondary electrons can lead to secondary electron signals (SE signals) that can likewise be detected simultaneously with etching and / or deposition treatments. By detecting the mentioned particles or the resulting signal during the etching and / or deposition treatments, the progress of the repair treatment can be monitored.

[0011] More specifically, correct and precise detection of the transition from the etching treatment on the defective material to the component material below the defect is critical to the success or failure of the repair treatment. This is also called endpointing. A precise endpoint may ultimately ensure that the mask to be repaired, after the end of the etching treatment, has the desired adsorption properties and / or phase shift properties and, for example, that the substrate material beneath the defective material is not affected and / or removed by the etching treatment. Since its high precision is required for wafer structure in the semiconductor industry, similar stringent requirements are placed on the restoration of microshadow masks.

[0012] By monitoring the etching process through the detection of backscattered and / or secondary particles formed during the etching process (on the material to be etched), a real-time image of the etching process can be obtained. Therefore, the transition of the etching process between materials can be determined by the changes in the aforementioned particle beam signal. However, in some cases, this contrast may be greatly reduced, for example, when the materials present in the etching process are only slightly different (e.g., have a similar atomic number), making it impossible to accurately determine the endpoint (the transition of the etching process from the defective material to the component material beneath the defect).

[0013] Despite this problem, various methods are known to achieve accurate results:

[0014] US Patent Publication US 2004 / 0121069 A1 discloses a method for repairing a phase-shifting mask using a charged particle beam system. This paper uses layout data from a scanning electron microscope as an alternative endpoint. Based on the elevation and surface slope of specific points, the layout data can be used to adjust the charged particle beam dose at each point within the defect environment.

[0015] US Patent 6,593,040 B2 discloses a method and apparatus for correcting phase-shift defects in a photomask. This includes scanning the photomask and performing three-dimensional analysis of the defects using an AFM (Atomic Force Microscope). Based on the three-dimensional analysis, an etching pattern is created, and a focused ion beam (FIB) is controlled according to the etching pattern to remove the defects. To improve the accuracy of the repair process, a sample of the FIB is produced and subjected to three-dimensional analysis.

[0016] However, such methods are both time-consuming and complex. In addition, the etching rate can never be accurately predicted, so despite the effort and complexity, optimal results cannot be obtained.

[0017] Therefore, there is a need to further improve the etching process for defects.

[0018] Secondly, however, there is always a need to improve diagnostic methods, such as for identifying (e.g., defective) lithography masking element materials. Subsequently, this diagnostic method can be used, for example, to tailor repair treatments for specific materials. [Summary of the Invention]

[0019] As described below, various forms of the present invention at least partially satisfy the above-mentioned needs.

[0020] One specific embodiment relates to a method for use with a lithography mask. In this case, the method may include guiding a particle beam in particles to a lithography mask element. Furthermore, it may include desorption and / or adsorption treatment of at least some gas particles in the region of the element. Additionally, the method may include capturing signals of secondary particles and / or backscattered particles and / or other free-space signals generated by the particle beam during the desorption and / or adsorption treatment.

[0021] The inventors of this invention have recognized that by inducing changes in the type and / or concentration of particles on a mask, it is possible to obtain corresponding captureable and time-variable signals, which can be generated by guiding a particle beam onto the mask, for example, signals of secondary particles (e.g., secondary electrons (SE) and / or backscattered electrons (EsB) when an electron beam is used as a particle beam). In particular, this can be accomplished by inducing adsorption and / or desorption processes of particles on the element (e.g., physical adsorption and / or chemical adsorption), for example, by disturbing the equilibrium of particles (e.g., with respect to desorption and adsorption), thereby re-establishing equilibrium (over time) in the time profile, and / or by changing at least one equilibrium determining parameter (e.g., the supply and / or (local) variation of the quantity of a particular particle and / or the supply of a class of (potentially existing) particles), thereby establishing a new equilibrium (over time).

[0022] Since (old or new) equilibrium can be established in different ways in the time profile, depending on the material of the element (surface) (e.g., due to different adsorption or desorption rates or different diffusion rates on the surface), the time profile of the signal can be specifically different, depending on the material of the element (surface).

[0023] Therefore, the (time-dependent) signals captured during adsorption and / or desorption processes (e.g., during equilibrium repair) can be material-specific and thus usable for a wide range of useful purposes. As detailed herein, the specific material of an element (e.g., a defect) can thus be identified, thereby allowing for the customization of subsequent element repairs (e.g., appropriate selection of repair parameters, such as the type or concentration of the treatment gas). Furthermore, the captured signals can be directly used at the endpoint during defect-related etching processes because they can be presented in different ways, for example, depending on whether the defect has not been completely removed (i.e., the time profile of the signal is still determined by the material of the defect) or has been removed (i.e., the time profile is determined by the element material arranged below the defect).

[0024] Particles in an atmospheric particulate environment are typically gaseous particles, such as gas atoms or gas molecules. Particles may be partially adsorbed or desorbed onto the element, allowing an equilibrium to be established between the particles and those adsorbed onto the element. Equilibrium can be understood, for example, as the state of the system under consideration, where the average number of freely moving particles and / or the average number of particles adsorbed onto the element is constant. In particular, the equilibrium state may relate to desorption and adsorption processes. Particles located on the element can also move through diffusion across the surface of the element, for example, from one region of the element to a location outside that region, and vice versa. In the following text, for ease of understanding, the term "gas particle" is often used in addition to the term "particle" for simplification, and the examples are not intended to be limited thereto. The term "gas particle" as used herein also explicitly refers to particles adsorbed onto the element (e.g., due to adsorption) or particles that move from the surface of the element to a region of the element (e.g., through surface diffusion).

[0025] The particles in the particle beam can be particles with mass, such as electrons, protons, ions, atoms, and molecules, but can also be high-energy particles, such as photons.

[0026] In this document, induced desorption and / or adsorption treatments can be made effective by externally acting on the coating rate or occupancy (German: "Belegung") of physically and / or chemically adsorbed particles (at least on the element). (The coating rate can be understood as, for example, the average number of particles adsorbed per unit time.) Acting on the coating can be understood here as disturbing the equilibrium coating (which is established at, for example, a specific temperature and a specific (partial) gas pressure of the particles). This can mean, for example, that after the equilibrium coating is disturbed, at least in the element region, the number of gas molecules (or the number of some other type of particles) is different from the number of gas molecules in this region before the equilibrium coating was disturbed. Then, for example, the disturbance can end, such that the equilibrium coating is re-established in the time profile. In addition, or additionally, it is also possible to act on the coating by setting a new equilibrium coating. This can mean, for example, that after a new equilibrium coating has been set, at least in the element region, the number of gas molecules is different from the number of gas molecules in this region before the setting. In the time profile, the coating can be changed accordingly from a first equilibrium coating to a second equilibrium coating.

[0027] In addition to the explained endpoints and material determinations, the morphology described herein also provides the possibility of determining, for example, whether undesirable changes have occurred on the surface near a defect being repaired. In the case of a lithography mask used for EUV lithography, a capping layer may be located between the adsorbent and the MoSi multilayer to act as a Bragg mirror. This capping layer may contain or consist of, for example, Ru. In this case, damage to the Ru layer near the defect should be avoided during repair. This can be determined in situ, for example, through the morphology presented herein. In particular, it may be determined whether a capping layer (e.g., a Ru capping layer) is present at a predetermined location and / or whether at least partially some other material is present there (e.g., because the capping layer has been at least partially damaged). This can be used both during defect repair and during the development of other repair processes (when performing a corresponding etching series). Repair parameters can be optimized to minimize damage to the capping layer.

[0028] This method may additionally include a selection element such that it comprises a predetermined material. This makes it possible, in particular, to assign captured signals to the predetermined material. Therefore, it is possible to assign separately captured signals to different predetermined materials. Therefore, it is possible to calibrate or reference measurements regarding different materials and / or material compositions of the element.

[0029] This method may additionally include at least one parameter storing the signal. The signal parameter may, for example, be stored together with at least one material-related parameter as reference data. For instance, at least one physical and / or chemical property of the material when interacting with the particle beam may be reflected in at least one parameter of the signal. This property may then be stored in the reference data. Alternatively, the name of the corresponding material may be used as a material-related parameter.

[0030] At least one parameter of the signal may be relevant, such as the rate of change of the captured signal, the gradient of the signal, the shape of the signal (e.g., intensity profile and time profile), the maximum value of the signal, the signal-to-noise ratio, etc. However, it is also possible to store (a portion) of the raw data of the signal as at least one parameter of the signal, or optionally even all of the raw data. Furthermore, it may be provided, for example, the time after a predetermined percentage of gas particles has been (re)adsorbed in the element region (e.g., after induced desorption and / or adsorption treatment has ended), for example, to capture the temporal dynamics of readsorption in this manner. For example, the readsorption time after a specific percentage (e.g., 90%) of adsorption has been reached at equilibrium (e.g., after the gas particles have been substantially removed) may be determined. This can be accomplished, for example, by capturing a signal in the form of a saturation curve and checking when the curve reaches a specific percentage of its saturation value.

[0031] This method may further include determining the component material based on at least one parameter of the comparison signal and at least one corresponding parameter of the stored reference data. The parameter may typically include any parameter mentioned above or in some other manner herein, or other suitable parameters.

[0032] As described herein, reference data can be determined. The corresponding parameters of the stored reference data can be directly stored in the reference data. However, the corresponding parameters used for comparison may also be derived only from the stored reference data. For example, parameters such as "gradient" and "maximum value" mentioned in the above examples may be included in the reference data. However, in extreme cases, the reference data may also store (only) a small amount of abstract data, such as raw signal data obtained during calibration measurements (using components of known materials). In this case, the required parameters may then be derived as needed.

[0033] Similarly, the steps described herein may be applied to components consisting of a plurality of material components.

[0034] The component may contain defects in the lithography mask. In this case, the defects in the lithography mask may include, for example, excess material on the lithography mask substrate. In this case, the excess material may affect the functionality of the lithography mask.

[0035] This method may additionally include guiding a particle beam to the defect, causing a localized etching process to occur at the defect. Furthermore, this method may include determining, at least in part, whether the localized etching process at the defect has been transformed into a localized etching process at a masking element arranged below the defect, based on signals captured during desorption and / or adsorption processes (e.g., during equilibrium repair).

[0036] It is possible, for example, that the expected time signal profile may change as long as the etching process has changed from the material of the defect to the material of the mask arranged below the defect. Based on the captured signal and, in particular, one or more parameters obtained from it (as described herein), it can be inferred whether the etching process used to remove the defect has ended. For example, if the material of the defect is still arranged on the mask surface (i.e., the etching process has not yet ended), the induced desorption and / or adsorption process may cause the signal to develop faster (or slower) over time, while if the defect has been (at least partially) removed, the expected signal to develop slower (or faster) over time when the induced desorption and / or adsorption process is performed, so that the component material arranged below the defect is located on the mask surface. For example, the material of the defect and the materials of the components arranged below the defect may result in different adsorption rates, desorption rates, and / or surface diffusion rates, resulting in different time profiles of the captured signal (e.g., processing at different rates).

[0037] This method may further include selecting at least one type of gas particles having an adsorption rate and / or desorption rate at a predetermined material of the defect, which differs from the adsorption rate and / or desorption rate at a material of a shielding element arranged below the defect by at least a predetermined threshold. This can be particularly done by means of a predetermined material involved. For example, as described herein, the material of the defect can be determined.

[0038] The requirement for the threshold (i.e., the quantitative characteristic form of the threshold) can be determined in particular by regard to the accuracy of signal capture. This may mean, for example, that if the accuracy of signal capture is quite low, the corresponding material-dependent resorption rates for at least one type of gas molecules should be significantly different from each other. In contrast, at relatively high capture accuracy, only relatively slight differences between resorption rates are sufficient. For example, one adsorption rate and / or desorption rate (e.g., at the defective material or at the element material arranged below the defect) may be at least 10%, 20%, 50%, 100%, 200%, or 500% higher than another corresponding adsorption rate and / or desorption rate (e.g., at the element material arranged below the defect or at the defective material).

[0039] In the preceding paragraphs, as repeatedly mentioned below, for clarity only (re)adsorption (e.g., via gas-phase adsorption and / or via surface diffusion) is referred to. However, examples of the corresponding explanation should be understood only by way of example, and similarly, desorption processes (e.g., into the gas phase or via surface diffusion) are also relevant.

[0040] Another state during the repair process, or typically during the equilibrium repair process during adsorption and / or desorption treatments, is as follows: the adhesion coefficient of particles (e.g., molecules) is generally inversely proportional to temperature. If, for example, there is a significant difference in the thermal conductivity and / or specific heat capacity of the materials of the defect and the underlying element (e.g., the substrate), the temperature decay profiles of the two materials after laser-induced molecular desorption will also be different. This effect can also be used to obtain different time profiles of the captured signal (e.g., processing at different rates), regardless of whether the two materials may have no other differences in their equivalent surface properties.

[0041] In addition, the substrate may be actively cooled. This helps to reduce the surface diffusivity of molecules. In this way, the capture of time-dependent signals during the repair process or typically during adsorption and / or desorption treatments can be simplified.

[0042] At least one external supply source may contain at least one precursor gas and / or one contrast gas. In particular, the contrast gas and / or precursor gas may be selected in a material-dependent and / or application-related manner. Advantageously, for example, desorption and / or adsorption treatment of the gas particles of the contrast gas may be induced. Subsequently, signals that change over time can be captured, for example, so that etching processes remain unaffected without changing the ratio associated with the precursor gas. This can be accomplished, for example, by selective desorption of the gas particles of the contrast gas, as will be described in more detail herein.

[0043] For example, a contrast gas may be selected such that the adsorption rate of the contrast gas on the component material (hereinafter often referred to as the masking material) arranged below the defect (at least on a time average) is higher (lower) than the adsorption rate of the contrast gas on the defect material (defect material). This may be accompanied by the desired requirement that the contrast material is better and / or faster (or to a lesser extent and / or slower) adsorbed on the material arranged below the component or defect. This can be for various reasons. For example, the contrast gas may exhibit a higher (lower) adsorption rate on the masking material than on the defect material through physical adsorption. Similarly or alternatively, the contrast gas may have a longer (shorter) residence time on the masking material than on the defect material due to chemisorption. These different adsorption properties can lead to a change in at least one (time-dependent) signal parameter and can be used to determine the etching process (or material analysis).

[0044] Alternatively or additionally, a contrast gas may be selected such that its affinity (coating rate, adsorption rate, and / or residence time) on the defect material is lower than that of the precursor gas used for the etching process. Alternatively or additionally, a contrast gas may be selected such that its affinity (coating rate, adsorption rate, and / or residence time) on the masking material is higher than that of the precursor gas used for the etching process. This can provide support here to make the endpoint more reliable, even if, for example, the precursor gas is adsorbed on the defect material and the masking material to the same extent and / or at the same rate.

[0045] Furthermore, the selection of the contrast gas may be based at least in part on the diffusion rate of the selected contrast gas on the defect material and on shielding materials that are as different as possible. This may have the effect that the capture of secondary particles and / or backscattered particles and / or some other free-space signals generated by the particle beam follows different temporal dynamics during desorption and / or adsorption processes (e.g., the contrast gas may be selected such that adsorption and / or desorption processes occur faster on the element material (e.g., after local removal of the contrast gas at or near the element) than on the material arranged below the element).

[0046] In this document, at least one precursor gas and / or contrast gas may already be contained in the gas particles at the start of this method. Additionally or further, it may be possible that only at least one precursor gas and / or contrast gas is supplied during this method, and / or the gas supply may be varied in each case to induce adsorption and / or desorption treatments.

[0047] The applicable comparative gas in this document may be one or more oxidizing agents, such as O2, O3, H2O, H2O2, N2O, NO, NO2, HNO3, and / or other oxygen-containing gases. Similarly, one or more halides may be used, such as Cl2, HCl, XeF2, HF, I2, HI, Br2, HBr, NOCl, NF3, PCl3, PCl5, PF3, and / or other halogen-containing gases. The applicable comparative gas may also include gases with reducing properties, such as H2, NH3, CH4, H2S, H2Se, H2Te, and other hydrogen-containing gases. The applicable comparative gas may include gases with low chemical reactivity, such as N2, He, Ne, Ar, Xe. It should be further noted that the aforementioned comparative gases may also be used as precursor gases.

[0048] The precursor gases used herein may be one or more (metal, transition element, main group) alkyl groups, such as cyclopentadienyl (Cp)- or methylcyclopentadienyl (MeCp)-trimethylplatinum (CpPtMe3 and / or MeCpPtMe3), tetramethyltin SnMe4, trimethylgallium GaMe3, ferrocene Cp2Fe, diarylchromium Ar2Cr, dicyclopentadienylruthenium Ru(C5H5)2, and other such compounds. Similarly, one or more (metal, transition element, main group) carbonyl compounds may be used, such as hexacarbonylchromium Cr(CO)6, hexacarbonylmolybdenum Mo(CO)6, hexacarbonyltungsten W(CO)6, octacarbonyldicobalt Co2(CO)8, dodecacarbonyltriruthenium Ru3(CO)12, pentacarbonyliron Fe(CO)5, and / or other such compounds. Similarly, one or more (metal, transition element, main group) alkoxides may be used, such as tetraethoxysilane Si(OC2H5)4, tetraisopropoxytitanium Ti(OC3H7)4, and other such compounds. Additionally, one or more (metal, transition element, main group) halides may be used, such as WF6, WCl6, TiCl6, BCl3, SiCl4, and / or other such compounds. Furthermore, one or more (metal, transition element, main group) complexes may be used, such as bis(hexafluoroacetyl acetone)copper Cu(C5F6HO2)2, dimethyltrifluoroacetyl acetone gold Me2Au(C5F3H4O2), and / or other such compounds. Furthermore, organic compounds may be used, such as CO, CO2, aliphatic or aromatic hydrocarbons, components of vacuum pump oil, volatile organic compounds, and / or other such compounds. It should be further noted that precursor gases listed as comparative gases may also be used.

[0049] Those skilled in the art will see here that the above list is not exhaustive, and any desired combination of contrast gas and precursor gas may be chosen, including choices beyond those cited, only by way of example.

[0050] Adsorption and / or desorption treatment herein refers to any treatment that results in a change in the coating on the surface of the element due to gas particles. This may occur, for example, by exchanging gas particles and / or by exchanging with portions of a shielding surface arranged around the element (e.g., by surface diffusion).

[0051] The induction may include, for example, (locally) removing gas particles from the element region. After the corresponding desorption, for example, the gas particles are completely removed from the element, and then the corresponding adsorption may occur, for example, by re-adsorption of gas particles and / or by diffusion from the surface of gas particles in the shielded portion (where the gas particles are not removed).

[0052] Additionally or further, the induction may involve altering the supply of gas particles. Regarding the supply of gas particles, the alteration may include, for example, changing the volumetric flow rate of the induction (e.g., increasing, decreasing, or shutting it off). In the case of a shut-off gas supply, gas particles may subsequently be transported substantially solely based on surface diffusion effects, for example, after gas particles have been removed from at least one region of the element (defect) as a result of the induction. This can also lead to a captureable time-dependent signal.

[0053] This can be understood as locally removing gas particles only in a portion of the area, where the gas particles are small relative to the total size of the lithography mask, for example, in a region ranging from 1 cm² to 1 mm², from 1 cm² or 1 mm² to 100 µm², less than 100 µm², for example, from 100 µm² to 1 µm², from 1 µm² to 100 nm², or from 100 nm² to 1 nm². However, it is also possible not to remove the particles locally, but to remove the entire lithography mask.

[0054] This method may further include the fact that gas particles are removed (at least partially) by means of a second particle beam and / or by means of an electric field and / or magnetic field applied to the element. In particular, partial removal of gas particles may be achieved by means of a second particle beam.

[0055] The energy supplied by the second particle beam can cause (local) heating of the substrate (i.e., the photomask material and / or component material). In this case, heating of the substrate can cause the removal of gas particles. For example, this can exceed the binding energy between the gas molecules and the substrate, as the binding can be dissociated. Furthermore, the energy supply may lead to selective excitation of the gas molecules. Selective excitation is understood herein as the coordination of the particle energy of the particle beam with the excitation spectrum of the gas particles. For example, a larger number of gas particles can therefore be removed. Furthermore, if multiple types (i.e., different gases) of gas molecules are present, for example, only the selected type of gas molecules can be excited; for example, only the contrast gas can be removed, but the precursor gas cannot be removed, and thus, for example, the etching process remains substantially uninduced. More generally, the second particle beam can be selected such that the wavelength assignable to the particle beam resonates only with a specific excitation energy from one of the different types of gas molecules (e.g., with at least a portion of the gas molecules present as the process gas and / or contrast gas). Excitation of gas molecules can have effects, for example, by transforming them into higher-energy vibrational, translational, and / or rotational modes, which can ultimately lead to the dissociation of the gas molecules from the substrate. Similarly, it is possible to match the wavelength of the particle beam with the absorption spectrum of the substrate, thereby, for example, enabling the substrate to be optimized and heated rapidly.

[0056] For a given second particle beam, a contrast gas may be further typically selected such that the absorption spectrum of the selected contrast gas can be excited by, for example, the second particle beam (as further described below), thereby facilitating the induced desorption process. In other words, the gas particles (e.g., the contrast gas) and the second particle beam can be coordinated with each other.

[0057] To increase the absorption of the particle beam by the material of the element (or defect) and / or the material arranged below the element (e.g., substrate), the composition of the material of the element and / or the material arranged below the element can be modified (in a targeted manner). This can be accomplished, for example, by doping, generating color centers, etc. Similarly, the material composition can be modified in a targeted manner during the production process by mixing with molecules to a specific effect, thereby obtaining a better beam absorption window in the material to be produced (e.g., within the wavelength range of the particle source that can be technically achieved at a lower cost). In a similar manner, the materials involved can be tuned – independently of the use of a second particle beam – to produce different physical and / or chemical adsorption properties and / or to make the diffusion rate of gas molecules on the material distinguishable. Preferably, the optical and mechanical properties of the photomask have the least possible adverse effects on the photolithography process.

[0058] In particular, the second particle beam may be implemented as a photon beam, such as a light beam, such as a laser.

[0059] The second particle beam can typically be homogeneous or heterogeneous, and can be monochromatic or polychromatic. In this case, the particle beam can be pulsed (non-empty factor < 1) or non-pulsed (e.g., CW, continuous wave).

[0060] Using pulsed particle beams offers advantages, particularly in ensuring the temporal resolution of individual particle beam pulses (i.e., the particle beam can be turned on for a duration of 10 milliseconds, for example, and off for 50 milliseconds, then turned on again for 10 milliseconds, thus allowing for the removal of gas particles in a pulsed manner). Furthermore, pulsed particle beams offer the advantage of providing significantly higher beam (or pulse) energy. This allows for the transmission of higher energy per unit time within the particle beam compared to CW particle beams. This makes it possible, for example, to remove a larger number of gas particles using a single pulse.

[0061] Furthermore, in each case, the same beam and scanning parameters can be used for both the (first) and second particle beams. For example, for both particle beams, the same accelerating voltage, the same beam current (in the case of charged particle beams), the same beam dwell time at a specific location, and the same beam line length (between the two locations to be scanned) may be provided. However, it is also possible that only some beam parameters are met. Similarly, it is possible that the beam parameters to be selected are completely different from each other.

[0062] Alternatively, the same (first) particle beam may be used for both inducing and capturing signals (regardless of its implementation). This could mean that the first particle beam (which may be directed onto a photomask element) could also be used to induce desorption and / or adsorption processes. In this case, a temporary and / or local increase in, for example, the intensity of the particle beam (e.g., expressed as the number of particles per unit time and / or the energy per particle) could be provided to enable induction (e.g., by removing gas particles). After induction, the intensity of the (first) particle beam could be changed back to its original value. It is conceivable, for example, to use a charged particle beam. Charged particles are understood herein as particles carrying a charge, such as electrons, protons, ions, charged molecules, etc. In addition, or additionally, neutral particle beams, such as atomic beams, molecular beams, photon beams, etc., may also be used.

[0063] In addition, or alternatively, it may be possible to remove gas particles by applying (optionally locally) an electric (or electromagnetic) field. An electric field herein is understood to mean a field caused by the separation of two opposite charges. The effect of the electric field on gas molecules may occur directly or indirectly herein, for example, by heating a shield with the assistance of an electric field. A direct effect may be achieved, for example, by removing the gas molecule from its bond with the substrate due to electrostatic interaction with the gas molecule. In other words, if the gas molecule has a negative charge, for example, an electric field caused by a positive charge can particularly attract negatively charged gas molecules to the positive charge of the electric field. This can also be achieved, for example, in uncharged particles by applying, for example, a gradient electric field.

[0064] Additionally or further, gas particles may be removed by applying a (optionally localized) magnetic (or electromagnetic) field. A magnetic field herein can be understood as a field generated by charge transport (e.g., by current flow). The use of a magnetic field makes it possible to generate a time-variable magnetic field and, for example, to achieve dissociation of the gas molecules from the substrate by heating the shield and / or the gas molecules (substrate) based on radio frequency. The use of a magnetic field makes it possible to control the extraction of gas molecules by utilizing the magnetic field (e.g., by utilizing the generated Lorentz force). Furthermore, if the gas molecules have magnetic dipole properties, it is possible to remove them by applying a magnetic gradient (in one or more spatial directions) through the force obtained on the magnetic dipole.

[0065] The capture signal may further include capture at at least two consecutive time points during desorption and / or adsorption treatment.

[0066] This method may further include determining the rate of change of the signal during desorption and / or adsorption treatments. Possibly, for example, the rate of change of the signal, or the re-adsorption rate of gas molecules in the element (or defect) region, is determined based on at least two capture signals (e.g., at at least two consecutive time points). A time-dependent re-adsorption treatment or rate of change can be understood as determining a (time-dependent) mathematical gradient of the re-adsorption treatment between two selected time points. In this case, the re-adsorption treatment may follow, for example, a saturation function.

[0067] The determination may further include comparing the measured rate of change with at least one predetermined rate of change. Therefore, the progress of the etching process at the lithography mask can be precisely determined because, for example, the time-dependent gradient (i.e., the second derivative of the time-dependent signal, e.g., at a predetermined time point after individual induction) can change after the etching process transforms into a gradient of the material beneath the defect. Based on the measured rate of change or gradient of the time-dependent signal, the progress of the etching process can be inferred by comparing it with a predetermined rate of change of the signal. If the gradient is below or above a predetermined threshold, this can be interpreted as, for example, the etching process approaching a termination criterion (e.g., associated with the etching process at the defect material transforming into the mask material). This is contingent on, for example, if the rate of change is above (below) a predetermined threshold, the etching process continues further. Conversely, if the rate of change is below (above) a predetermined threshold, this can be used as a criterion for terminating the etching process. For clarity, it should be noted that during the etching process, for example, adsorption and / or desorption processes can be repeatedly induced in the same manner (e.g., by applying laser pulses and / or other components explained herein), and in each case, the resulting corresponding capture signal is observed to change over time (and may change after the etching process transition). Similarly, the material of the component can often be determined in this way without the presence of defects and / or etching processes. In this case, the change of the signal over time may also be averaged during repeated induced adsorption and / or desorption processes to improve the signal-to-noise ratio. For example, in each case, at least two, at least five, or at least ten signal profiles can be used for averaging.

[0068] It is conceivable that the intensity of the capture signal to be captured is (only) at a first time point during the desorption process and additionally (only) at a second time point during the desorption process. Similarly, it is possible that the signal to be captured is at a first time point during the adsorption process and additionally at a second time point during the adsorption process. Furthermore, it is possible that the signal to be captured is first located at a first time point during the desorption process and subsequently at a second time point during the adsorption process.

[0069] Furthermore, it is possible that the captured signal includes a time profile of the captured signal during the desorption and / or adsorption treatment. This can be done, for example, within a predetermined (time) interval. Additionally, it is also possible to determine at least two disjoint time profiles of time-dependent signals during the same induced adsorption and / or desorption treatment, and to combine these at least two time profiles with each other. The captured time profile(s), etc., can be compared with at least one stored signal time profile (e.g., for materials analysis and / or for endpoints).

[0070] The captured signal may initially (i.e., close in time to induction, e.g., removal of gas molecules; e.g., 1 ms, 5 ms, or 10 ms after induction) have a higher gradient than at points further in time than induction (e.g., 50 ms after induction). This could mean that the signal becomes flatter over time, i.e., the gradient of time-dependent re-adsorption treatment decreases, for example, according to a saturation curve.

[0071] The captured signal profile can also be stored (along with existing information about the component material) so that it can be used as a reference for future measurements, as described herein regarding reference data. Under this application, a definite and optionally stored time-dependent profile of the signal can be provided for different materials of the component and / or materials arranged below the component.

[0072] The captured signal time profile can be compared with at least one stored (predetermined) time profile, for example, to infer etching process and / or material determination.

[0073] The capture time profile is understood in context such that the captureable time-dependent signal is represented by at least three data points. For example, the signal can be captured repeatedly per unit time (e.g., at a rate of 100 Hz, 1000 Hz, etc.) so that at least a portion of the induced transition from the disturbed equilibrium back to the original equilibrium or back to a further equilibrium (e.g., a time period, such as 1 millisecond, 10 milliseconds, etc.) can be represented. In principle, the signal profile is preferably represented by multiple data points.

[0074] However, storing the signal profile, for example, may also be sufficient to capture the corresponding signal only at a predetermined time point or within a predetermined short time window (after induced desorption and / or adsorption treatment) at subsequent time points (for endpoints and / or for material analysis), wherein this can then be compared with the corresponding value of the stored signal profile at this time point or within this time window. Alternatively, it may be possible, for example, to determine the signal parameter at a predetermined time point or within a predetermined time window (e.g., gradient) and compare it with the corresponding value of the stored signal profile at this time point or within this time window.

[0075] In this case, the signal can be captured (only) during a defined (e.g., short) time window during the transition from the induced disturbance to the original equilibrium or to a further equilibrium. In this case, the time window can be designed such that, for example, 1%, 5%, 10%, 20%, 50% of the total time required for the re-establishment of equilibrium is captured (this time can be an approximation, for example, after which the removed gas particles are substantially re-adsorbed, which can be specified as, for example, t = 1 / adsorption rate). It is also possible to capture the signal during two or more such time windows. Therefore, the measurement duration of the captured signal can remain relatively short compared to capturing the entire formation (of the original or further equilibrium).

[0076] The capture may additionally include capturing a signal at at least one predetermined time point after the induced desorption and / or adsorption treatment. In this case, the time point may correspond to the sampling window of the data point. In this case, the method may be carried out in such a way that the capture signal is achieved, for example, 5 milliseconds after the induced desorption and / or adsorption treatment (or at any other suitable time point). Thus, for example, the amount of data generated due to the capture can be reduced, and the capture can be limited to this time point and / or the subsequent (time) region of the desorption and / or adsorption treatment, which is potentially meaningful (i.e., statements about the etching treatment and / or the material can be made on this basis). For example, a suitable time point may be given, for example, by the time after the removed gas particles are re-adsorbed to a relatively large extent, which may be approximated, for example, t = (0.5 / adsorption rate of the element). If the expected coating has not (yet not yet) occurred or has (already) occurred to a large extent at this time point, it can be inferred that, for example, the material (and therefore the adsorption rate) has changed, which can be used as the endpoint.

[0077] For example, the signal strength at a predetermined time point after induction (or after the end of induction) may be determined and compared with the value of at least one strength at the same time point, which comes from, for example, stored reference data (e.g., for material analysis and / or for endpoints).

[0078] This method may additionally include synchronizing capture and induction. This makes it possible to establish a fixed time relationship between capture and induction. In this case, it is possible that capture and induction begin simultaneously (automatically). Alternatively, on the other hand, a time offset may be provided between induction and the start of capture (e.g., capture may begin 10 milliseconds after induction (or at any other suitable time)). It is also possible that capture has already begun at a time point before the start of induction, so as to capture, for example, induction dynamics simultaneously. Therefore, it is possible, for example, to perform an automatic routine, which generates, for example, a material-specific capture signal by pressing a button once (thereby storing the corresponding reference data or making material determination possible and / or allowing the endpoint).

[0079] Furthermore, (at least) the following steps are possible: inducing desorption and / or adsorption treatment, capturing signals, and determining whether at least local etching treatment at the defect has been transformed into elements arranged below the defect, and repeating (preferably periodically). This provides an advantage, in particular, that repeating these steps allows for iterative (and more precise) monitoring of the etching treatment of the defect by means of masking elements arranged below the defect. In this case, performing these steps periodically can be understood as meaning repeating these steps at equidistant time intervals. In other words, it is therefore possible, for example, to perform these steps once per second, once per minute, once per hour, etc. Furthermore, it is also possible to perform these steps at a high frequency, i.e., multiple times per second (e.g., 10 times per second, 100 times per second, etc.). Depending on the requirements, high-frequency measurements may be advantageous so that the endpoint is maintained for a shorter period of time relative to the duration of the repair treatment performed.

[0080] These steps may also be performed directly and sequentially or almost continuously, that is, after the last (processing) step is completed, the first (processing) step of the subsequent iteration of the method can be performed directly.

[0081] In this case, the preferred cycle for performing those steps may depend at least on the processing speed of the etching and / or desorption and / or adsorption processes, that is, when there is a higher processing speed, it is preferred to perform those steps more often than when the processing speed is lower.

[0082] This disclosure further covers an apparatus for use with a lithography mask. The apparatus may include components for guiding a particle beam in gas particles to a lithography mask element, and components for inducing desorption and / or adsorption processes of at least some gas particles in the element region. Furthermore, the apparatus may include components for capturing signals of secondary particles and / or backscattered particles and / or other free-space signals generated by the particle beam during the desorption and / or adsorption processes.

[0083] This device can be configured to automatically perform the methods described herein, for example, after a single button press.

[0084] In this case, the component for guiding the particle beam may include, in particular, a focusing component, such as a focusing optical unit. In this case, the component for capturing the signal may be configured for various detectors, which are sensitive to the type of backscattered and / or secondary particles and / or to any other free-space signals induced by the particle beam. Furthermore, the component for capturing the signal may include corresponding data recording and further processing devices. These can be understood as, for example, DAQ cards, signal amplifiers, filters, computers, servers, databases, software (for control devices and / or for data analysis), etc.

[0085] The device may further include components for determining the material of the element based on at least one parameter of the comparison signal and at least one corresponding parameter of the stored reference data.

[0086] The apparatus may further include components for guiding the particle beam onto the element, causing a localized etching process to occur at the element. In this example, the element may contain a defect, for example, causing a localized etching process to occur at the defect. Furthermore, the apparatus may include components for determining, at least in part, whether the localized etching process at the defect has been transformed into a localized etching process at a (further) element of a mask arranged below the defect, based on signals captured during the desorption or adsorption process. Components for determining may further include a database. In this case, the database may store one or more stored signals (e.g., temporal profiles of captured signals), which can be compared with the (existing) captured signals by the components used for determination to draw conclusions about the etching process.

[0087] The inducing member may additionally include a component for (partially) removing gas particles from the element region. Possible embodiments of the (partially) removing gas particle component have been further described above.

[0088] The apparatus may further include components for generating a second particle beam to at least partially remove gas particles and / or for generating an electric field and / or a magnetic field to at least partially remove gas particles. The components for generating the second particle beam may include, for example, an electron beam source. Furthermore, the components may include a laser beam source, meaning the second particle beam may be, for example, a laser beam. Additionally, the components for generating the second particle beam may include components for generating an ion beam or an uncharged atomic or molecular beam.

[0089] In this case, the component for generating the electric field may include, for example, a capacitor. In this case, the component for generating the magnetic field may include at least one conductor through which current flows. In this case, the conductor through which the current flows may be wound into at least one coil (e.g., a Helmholtz coil, a Maxwell coil, a Buck coil, etc.). The component for generating the magnetic field may further include a component for generating a constant current, thereby minimizing the uniformity fluctuations and time drift of the magnetic field within the coil.

[0090] In addition, (additional) oscillators for electric fields and magnetic fields may be provided to generate time-variable electric and / or magnetic fields in each case, for example, in the radio frequency (RF) range.

[0091] The components for capturing the signal may be further configured to capture the signal (only) within one or more predetermined time windows or time points associated with the induced desorption or adsorption treatment. Such time windows or time points may be specifically embodied as explained herein with respect to the method.

[0092] The capturing component may additionally include components for synchronizing capturing and induction. In this case, the synchronization component (if implemented in hardware) may include at least one oscillator or clock generator to synchronize capturing and induction.

[0093] This disclosure may be further implemented as a computer program containing computer-executable code, which, when executed, causes the computer to perform any of the features described herein.

[0094] This disclosure further relates to an apparatus that can be configured as described herein and includes a computer. A computer program can be stored and / or executed thereon. The computer program can be configured to cause the apparatus to (automatically) perform the method steps described herein, for example, to analyze a material upon pressing a button, or, for example, (fully automatically) during the same etching process.

[0095] Regardless of whether the form of this application is explicitly described as a method, a computer program and / or a component, they can in every case be embodied as a method, a computer program (or a part thereof) or a component of a corresponding device.

[0096] Furthermore, the features described herein can generally be embodied in hardware, software, firmware, and / or combinations thereof. If implemented in software / firmware, such features can be implemented on a computer-readable medium or as one or more instructions or code on a computer-readable medium. A computer-readable medium encompasses computer storage media and communication media, including all media that enable a computer program to be transferred from one location to another. A storage medium can be any available medium accessible by a computer. Examples may include RAM, ROM, EEPROM, FPGA, CD / DVD or other optical disc storage devices, magnetic disk storage devices or other magnetic storage devices, or any other medium.

[0097] It should be further noted that the present invention is not limited to the specific combinations of features explicitly stated herein. The combinations explicitly stated herein should be understood as examples only. Similarly, other features and / or combinations of features are contemplated.

Implementation Method

[0102] Specific embodiments of the present invention are described below primarily with reference to lithography masking (and its repair). However, the present invention is not limited thereto; it can also be used for other types of masking processes, or even more commonly for general surface treatments or inspections, such as for other objects in the field of microelectronics, for example, for inspecting, modifying, and / or repairing structured wafer surfaces or microchip surfaces. For example, it may repair defects that are typically arranged above a surface or surface element. Even though the application of treating a masked surface is therefore primarily referred to below, for the sake of clarity and ease of understanding, those skilled in the art will keep in mind other possible uses of the teachings disclosed.

[0103] In particular, in the context of the specific embodiments detailed below, it is also possible to make (e.g., defective) component material decisions.

[0104] It should be further noted that only specific embodiments of the present invention will be described in more detail below. However, those skilled in the art will understand that the features and modification options described with respect to these specific embodiments can be further modified and / or combined with each other in other combinations or supplementary combinations without departing from the scope of the present invention. In addition, if individual features or sub-features are optional to achieve the desired result, they may be omitted. To avoid unnecessary repetition, the notes and explanations in the preceding sections are retained in their validity for the embodiments described below.

[0105] Figure 1 shows various schematic diagrams of the endpoint of induced desorption of gas molecules during electron beam-induced etching on a lithography mask.

[0106] The upper left portion of Figure 1 (denoted as A in Figure 1) shows a first (substrate) layer 1, on which a second layer 2 is arranged. Located on the second layer 2 is a defect 3 region, which in this example consists of excess material arranged on the first layer 1. This excess material (i.e., the defect 3 region) is intended to be removed to the first layer 1 to repair the defect. In this case, removal can be achieved by particle beam-induced etching, that is, by guiding a first particle beam 4 (e.g., an electron beam; see the right side of Figure 1A) to the defect 3 region in the presence of gas molecules (e.g., a precursor gas and / or a contrast gas).

[0107] In this case, monitoring the etching process is particularly important to prevent the first layer 1 from being unintentionally etched. This can be achieved, for example, by the endpoint – described in this disclosure – through the induced desorption of particles (e.g., molecules) and the analysis of the adsorption or resorption of particles (e.g., molecules).

[0108] In the undisturbed state, the relevant desorption and adsorption of gas molecules in the defect 3 region and at the first layer 1 are in equilibrium. By at least locally disturbing the equilibrium, it is possible to remove some of the (gas) molecules adsorbed on the defect 3. Preferably, this disturbance can be induced by a second particle beam 5. Figure 1 shows that the second particle beam 5 (e.g., a laser) can be guided onto the defect 3 region.

[0109] By guiding the second particle beam 5 to the defect region 3, it is possible to remove gas particles from the defect region 3. This can be achieved, for example, by local heating 6 of the location to be repaired (i.e., the defect region 3). Due to the local heating of the defect region 3, gas molecules adsorbed in the defect region 3 can begin to desorb, thus leaving their original adsorption sites in the defect region 3. However, as described herein, other mechanisms for removing gas particles may also be possible. Furthermore, it is possible to remove particles from the defect region 3 without guiding the second particle beam to the defect region 3, for example, by guiding it to an adjacent region.

[0110] The removal of gas particles can be understood as disrupting the original equilibrium of desorption and adsorption of gas molecules at point 7. As a result of disrupting the equilibrium at point 7, after the second particle beam 5 has been shut off, the gas molecules may return to the original equilibrium (e.g., through adsorption) or change to a new equilibrium (provided, for example, the gas supply is also changed). In this case, such return to the original equilibrium state or the new equilibrium state may depend on the material (as described herein). Such a return is depicted in the upper right corner of Figure 1.

[0111] By guiding the first particle beam 4 to the defect 3 region, it is possible to generate a signal consisting of backscattered electrons 8 (EsB signal) and / or secondary electrons 9 (SE signal) and / or some other free-space signal 10 generated by the etching beam, which can be captured. Since this signal can depend on the coating of the defect 3 and the gas particles, the captured signal can reflect the dynamics of the recoating with the gas particles.

[0112] The result of disrupting the equilibrium 7 is that, during the system's transition back to the original equilibrium or to a further equilibrium, the generated and captureable signals across time points t1, ..., tn are also subject to temporal dynamics, which can be reflected in the number of captureable backscattered electrons (EsB signal 8) and / or secondary electrons (SE signal 9) (in the time profile). In this paper, these signals may depend on the adsorption of gas molecules in the existing defect 3 region. This makes it possible to track or monitor the return to the original or further equilibrium state.

[0113] In one exemplary embodiment, starting from the time point when the second particle beam 5 is turned off, the EsB signal 8 at the defect 3 region may increase at time points t1 and t2 due to (again) increased adsorption of gas molecules (that is, it may capture, for example, more backscattered electrons per unit time). This description is in the top center of Figure 1. During the same time interval under consideration, for example, the SE signal 9 may decrease at time points t1 and t2 (that is, it may capture, for example, fewer secondary electrons per unit time). This is also described in the top center of Figure 1.

[0114] In the context of this disclosure, it is possible to capture this (or that) time-dependent signal and use it to determine the etching process on the lithography mask. Since the recoating using gas particles can be material-dependent, the temporal dynamics of the signal can also be material-dependent. Therefore, the temporal profile of the signal can change during the etching process from etching defect 3 to etching the underlying substrate 1. In this case, there may also be a reliable endpoint, in particular if there is no measurable difference in the signal at defect 3 and in the individual equilibrium states at substrate 1 during etching.

[0115] The following explanation refers to the lower region in FIG1 (denoted by B in FIG1). It should be emphasized that, in a further specific embodiment, using an experimental setup similar to that described with reference to FIG1, the EsB signal 8 and / or SE signal 9 can be used to determine the material in the defect 3 region by restoring the gas molecules to their original equilibrium state or a further equilibrium state of being trapped (which represents the same time dynamics) in a time-dependent manner and comparing it with reference data. For this purpose, an etching process is not necessarily required.

[0116] The lower region (part B) of Figure 1 shows one possible exemplary state of a further advancement of the repair process on the lithography mask. It is assumed in this document that at this point in time, the excess material initially arranged above the first layer 1 and causing the formation of the defect 3 region has been removed, and the etching process is transformed into an etching process on the first layer 1 of the lithography mask.

[0117] As described above, by guiding the second particle beam 5 to the defect region 3, it is possible to re-determine the etching process in the defect region 3. As described above, the equilibrium of desorbed and adsorbed gas molecules in the defect region 3 can be disrupted again by local heating 6, after which the gas molecules return to their original equilibrium state or a further equilibrium state. Again, after the equilibrium is disrupted, the EsB signal 8 and / or the SE signal 9 and / or a further free-space signal 10 may be generated by the first particle beam 4. By capturing the signal(s), as described above, it is possible to observe or monitor the (time-dependent) transition of gas molecules from the disturbed equilibrium state. In this case, as described above, the signal intensity of the EsB signal 8 may increase in the time profile, while the signal intensity of the SE signal 9 may decrease in the time profile. However, other configurations are also conceivable.

[0118] Increased removal of material from defect 3 (i.e., with increased etching) can cause adsorbed gas molecules to move closer to the first layer 1. This can typically alter the binding strength of gas molecules over time (i.e., with increased etching) (e.g., enhancing or weakening the binding strength, depending on the choice of gas molecules (as described above) and the materials contained in the first layer 1 and defect 3). Meanwhile, during the etching of defect 3 (Fig. 1, top), the time-dependent signal that can be captured may differ from that during the etching of the first layer 1 (Fig. 1, bottom). Even if the signal is not different at individual starting points (e.g., before induction or directly in equilibrium after the removal of gas particles), the signal may exhibit a different time profile. For example, after the etching process transitions to the etching of the first layer 1, the captured signal may recover to equilibrium (more and more slowly or quickly) (e.g., because the adsorption of gas particles on layer 1 is slower or faster than on defect 3). In this respect, for example, at the defect, signal intensities similar to those during such etching periods can be detected at other times t3 and t4, as shown in the bottom center of Fig. 1. For example, by comparing individual time points, it is possible to reliably detect changes in the etching process.

[0119] In this case, it is possible to perform the above-described method steps periodically (as described herein). Similarly, it is conceivable to perform the method steps only at appropriate times, for example, at a time when a transition in the etching process is expected. Similarly, it is conceivable to initially perform the method steps occasionally (e.g., once, twice, etc.), and then periodically if a transition is expected. Similarly, it is conceivable to perform the method steps only after, for example, the operator of the etching apparatus explicitly activates the button (e.g., a physical button, a GUI button, etc.).

[0120] Figure 2 shows a schematic diagram of the method steps for disturbing the equilibrium state while supplying external energy and for capturing time-dependent signals after returning to equilibrium.

[0121] In a possible specific embodiment according to FIG2, it is conceivable herein that the original equilibrium state 11 in a component region (e.g., defect 3 region in FIG1) is to be disturbed by the desorption and adsorption of gas molecules through the supply of energy 12 (e.g., in the form of a particle beam (e.g., a light beam or laser)). As mentioned above, the disturbance can be caused, for example, by at least locally heating the component region. As explained above, this can result in a state 13 of at least locally altered number of gas molecules (or at least one species of gas molecules) adsorbed in the component region.

[0122] As a result of the locally altered state 13, a time-dependent process can be ensured that gas molecules return to their original equilibrium state or a further equilibrium state 14 after the energy supply has been shut off. In this case, it is possible to capture time-dependent signals, such as the time-dependent intensity of backscattered electrons (EsB signals) and / or secondary electrons (SE signals) at various time points t1, ..., tn, denoted herein as ISE(t). In this case, the captured signal can indicate that the element region is repaired at least partially by gas molecules (or at least one species of gas molecules). Therefore, the captured time-dependent signal ISE(t) makes it possible to infer the progress of the etching process (as described above) and / or to determine the element material.

[0123] Figure 3 shows a schematic diagram of the method steps for disturbing the equilibrium state while changing the gas molecule supply and for capturing time-dependent signals after the transition to equilibrium.

[0124] In a further embodiment (which may also be combined with the embodiment according to FIG. 2), by altering the external gas supply 15 of at least one species of gas molecules, an equilibrium state 11 of desorbed and adsorbed gas molecules in the disturbance element region (e.g., defect 3 region in FIG. 1) can be provided. This may include, for example, reducing or turning off (or increasing), for example, the external gas supply of a precursor gas.

[0125] Due to the reduction (increase) in the external gas supply and the absence of (more) gas molecules being subsequently transported, the equilibrium-related drift or desorption (or adsorption) of gas molecules (or at least one species thereof) adsorbed in the element region can be ensured. Therefore, a state of reduced (increased) coverage 16 in the element region can be established.

[0126] This can change over a time profile spanning time points t1, ..., tn, towards, for example, the state of gas molecules 17 that are almost completely desorbed in the element region. In particular, the transition towards almost completely desorbed gas molecules 17 can here be represented by a captureable, time-variable signal ISE(t). In this case, the time-variable signal ISE(t) can represent the temporal dynamics of desorption, which can depend in particular on the material-dependent bonding or affinity of the gas molecules (or at least one species thereof) to the material of the element region. This makes it possible to monitor the etching process (as described above) or to determine the material of the element region.

[0127] When the gas supply is shut off during etching processes on different materials, it is also possible for at least one species of gas molecules to be "consumed" at different rates by electron beam-induced processing. In this way, corresponding time-variable signals will also allow conclusions to be drawn about individual materials, for example, for endpoints, for material identification and / or for inspecting coatings.

[0128] In the two specific embodiments shown in Figures 2 and 3, at least one further material (as shown in Figure 1) may be provided for the location below the element (or defect) region. In this case, it may be necessary to select gas molecules or species such that the latter have different affinities for the materials involved. If the gas molecules adsorb onto the two materials in a characteristically realized manner at different rates, this can lead to the distinguishability of the time-dependent signal ISE(t).

[0129] In this case, as described above, when the etching process on the photomask is to change the material of the element / defect to the material of the mask arranged below the defect, it is particularly desirable to select gas particles that cause changes in the signals of secondary particles and / or backscattered particles and / or some other free space signals generated by the particle beam.

[0130] Furthermore, a combination of method steps for determining the material of an element (e.g., a defect) and the endpoint according to the invention can be provided. It is conceivable that method steps for determining the material in the defect region 3 are first performed. Based on this, at least one species of gas can be selected such that a better standard (as described above) for distinguishability of desorption and / or adsorption at the material in the defect region 3 and / or at the first layer 1 can be achieved. Based on this, a particle beam-induced etching process (optionally applicable to specific defect materials) can then be added (as described above) to apply the endpoint according to the invention and customize the material actually present.

[0131] In all specific embodiments, capture can be implemented in a variety of ways. For example, it is possible to divide the area of ​​an element (e.g., a defect) into at least one set of pixels. In this case, a pixel may contain one (square) sub-region of the area, for example, a 10% area ratio (although there may be any other area ratio). In this case, capture may be configured such that it includes "scanning" the area with at least one set of pixels using an electron beam (or any other desired particle beam). Alternatively, it is also possible to capture only a single pixel or a single (selected) pixel of the area or location to be repaired.

[0132] In a further specific embodiment (not shown in the figures), material for identifying defects (as described above) can be provided before the etching process begins. In this case, material for identifying defects can be provided by applying the method described herein. This knowledge of the defect material makes it possible to select a type of gas particles that can be located around the defect, such that the adsorption and / or desorption rates of the gas particles at the defect are different from the adsorption and / or desorption rates of the gas particles at the masking element material arranged below the defect.

[0133] In this case, the requirement for difference may depend, for example, on the measurement configuration used. If the measurement is subject to, for example, the effects of perturbing variables (e.g., electron noise, low capture accuracy of backscattered particles), which reduces the signal-to-noise ratio, it can be considered advantageous to select the type of gas particles such that the adsorption and / or desorption rates of the two materials involved are different from each other to the greatest extent possible. This (desired or required) difference can be specified in particular by the definition of a threshold. In this regard, it may be provided, for example, that the adsorption and / or desorption rates of the materials involved should differ from each other by at least 10%, 20%, 50%, 100%, 200%, 500%, etc. In this regard, it is possible to detect possible accuracy losses as accurately as possible during the detection of the etching process transition (as described above), even under relatively unfavorable measurement parameter conditions (e.g., when perturbing variables are present).

[0134] In contrast, with higher measurement accuracy, the prerequisite is that the requirements for the expected differences in the adsorption and / or desorption rates of the materials involved are less stringent compared to with lower measurement accuracy. In this case, it can be provided that, for example, the adsorption and / or desorption rates of the materials involved should differ from each other by only 10%, for example, so that the etching process can be monitored in a cost-effective manner, because, depending on the needs, it is possible to obtain a more cost-effective type of gas particle. [Simplified Explanation of the Diagram]

[0098] The following detailed description refers to the following drawings to describe possible specific embodiments of the present invention:

[0099] Figure 1 shows a schematic diagram of the endpoint of induced desorption of gas molecules during particle beam induced etching on a lithography mask;

[0100] Figure 2 shows a schematic diagram of the induction induced by supplying external energy;

[0101] Figure 3 shows a schematic diagram of the effect induced by changing the external gas supply.

Claims

1. A method for an object in the field of microelectronics, comprising: a. guiding a particle beam (4) and at least one external supply source (15) for supplying at least one gas particle to a defect (3) of the object in the field of microelectronics for locally etching the defect (3) and / or locally depositing material on the defect (3); b. inducing a time and / or local variation of a desorption and / or adsorption treatment (7) of at least one gas particle in the region of the defect (3), thereby disturbing the original equilibrium of the desorption and / or adsorption treatment (7) by at least one of the following methods during the guiding of the particle beam (4) and the supply of at least one gas particle: temporarily applying an electric field and / or a magnetic field; temporarily changing the manner of supplying at least one gas particle; or temporarily irradiating a region adjacent to the defect (3) with a second particle beam (5); and c. capturing signals of secondary particles (9) and / or backscattered particles (8) and / or some other free-space signals (10) generated by the particle beam (4) during the recovery of the desorption and / or adsorption process to the original equilibrium or a new equilibrium. The capture of the signal includes a time profile of the capture of the signal during the desorption and / or adsorption treatment; and the capture of the signal includes capture at least two consecutive time points during the desorption and / or adsorption treatment, and determination of the rate of change of the signal during the desorption and / or adsorption treatment for determining the change of defect (3) material.

2. The method as described in claim 1, wherein capturing the signal during the desorption and / or adsorption process includes capturing the transition from the disturbed equilibrium to the original equilibrium or a further equilibrium.

3. The method as described in claim 1 further includes selecting a component such that it comprises a predetermined material.

4. The method as described in claim 3 further includes storing at least one parameter of the signal and at least one parameter associated with the material as reference data.

5. The method as described in claim 1 further comprises: determining the material of the defect (3) by comparing at least one parameter of the signal with at least one corresponding parameter of stored reference data.

6. The method as described in claim 3, wherein the component comprises the defect (3) of the object in the field of microelectronics.

7. The method as described in claim 6 further comprises: directing a particle beam (4) onto the defect (3) such that a local etching process occurs at the defect (3); and determining, at least in part based on a signal captured during the desorption and / or adsorption process (7), whether the local etching process at the defect (3) has been transformed into a local etching process at another component (1) of the object arranged below the defect (3) in the microelectronic field.

8. The method as described in claim 7 further comprises selecting at least one particle having an adsorption rate and / or desorption rate at a predetermined material of the defect (3), the adsorption rate and / or desorption rate of which differs by at least a predetermined threshold from the adsorption rate and / or desorption rate at the material of the other component (1) of the object arranged below the defect (3) in the microelectronic field.

9. The method as described in claim 1, wherein the at least one external supply source (15) contains at least one precursor gas and / or one contrast gas.

10. The method as described in claim 1, wherein inducing includes locally removing particles from the defect (3) region and / or altering the particle supply.

11. The method as claimed in claim 1, wherein the object in the field of microelectronics includes at least one of the following groups: a photomask, a wafer, and a microchip.

12. The method as claimed in claim 1, wherein the removal of particles is achieved by means of a second particle beam (5) and / or by means of an electric field and / or a magnetic field applied to the element.

13. The method as described in claim 1, wherein capturing includes capturing the signal at at least a predetermined time point after inducing the desorption and / or adsorption treatment.

14. The method as described in claim 1 further includes synchronizing the capture with the induction.

15. An apparatus for an object in the field of microelectronics, comprising: a. a component for guiding a particle beam (4) and at least one external supply source (15) for supplying at least one gas particle to a defect (3) of the object in the field of microelectronics, for locally etching the defect (3) and / or locally depositing material on the defect (3); b. a component for inducing a time and / or local variation of a desorption and / or adsorption treatment (7) of at least one gas particle in the region of the defect (3), wherein, during guiding the particle beam (4) and supplying the at least one gas particle, the original equilibrium of the desorption and / or adsorption treatment (7) is disrupted by at least one of the following methods: temporarily applying an electric field and / or a magnetic field; temporarily changing the manner of supplying the at least one gas particle; or temporarily irradiating a region adjacent to the defect (3); and c. A component for capturing signals of secondary particles (9) and / or backscattered particles (8) and / or some other free-space signals (10) generated by the particle beam (4) during the desorption and / or adsorption process to return to the original equilibrium or a new equilibrium; wherein capturing the signal includes capturing the signal over a time profile during the desorption and / or adsorption process; and wherein capturing the signal includes capturing it at at least two consecutive time points during the desorption and / or adsorption process, and determining the rate of change of the signal during the desorption and / or adsorption process for determining the change of the defect (3) material.

16. The apparatus as claimed in claim 15 further includes a component for determining the defect (3) of material based on comparing at least one parameter of the signal with at least one corresponding parameter of stored reference data.

17. The apparatus as claimed in claim 15 further comprises: a component for guiding a particle beam (4) onto the defect (3) such that a local etching process occurs at the defect (3); and a component for determining, at least in part, based on a signal captured during the desorption or adsorption process (7), whether the local etching process at the defect (3) has been transformed into a local etching process at another component (1) of one of the objects arranged below the defect (3) in the microelectronic field.

18. The apparatus as claimed in claim 15, wherein the inducing member includes a component for locally removing particles from the defect (3) region.

19. The apparatus as claimed in claim 18, wherein the removal member includes a member for generating a second particle beam (5) for removing particles and / or for generating an electric field and / or a magnetic field for removing particles.

20. The apparatus of claim 15, wherein the component for capturing the signal is configured to capture within one or more predetermined time windows or time points related to inducing the desorption or adsorption process.

21. The apparatus as described in claim 15 further includes a component for synchronizing the capture and the induction.

22. A computer program comprising computer-executable code that, when executed, causes a computer to perform the methods described in any one of claims 1 to 14.

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