Patent Description:
Lithography is the foundation of the semiconductor industry. The rapid development of the semiconductor industry can be attributed to the rapid development of the lithography. When facing the growing quantity of logic gates in an integrated circuit, the conventional manufacturing process is, however, under severe challenge.

Among different lithography technologies, photo lithography is the most important one. Photo lithography aligns a radiation source to an exposure target through a patterned mask (e.g., a photo mask or a reticle) so as to project the circuit pattern drawn on the mask to a corresponding location of a substrate (e.g., a wafer) coated with light-sensitive material (e.g., the photo resist). Since photo lithography is cost-effective and suitable for being integrated into mass production and processing applications of the semiconductor, photo lithography process and related apparatus will remain their key positions in the semiconductor industry under continuous development of advanced processes.

Optical lithography used in semiconductors has the following requirements, including: high resolution (e.g., accurately adjusting the focal point), reducing the exposure wavelength and also increasing the numerical aperture (NA) of lens, high-sensitivity photosensitive materials, alignment accuracy, precise process parameter control, and low defect density (e.g., by detecting masks in advance to improve exposure yield).

The feature size of the lithography process pattern is limited by the wavelength of the projected radiation source, and thus more and more advanced processes use deep ultraviolet (DUV) or extreme ultraviolet (EUV) as the radiation source of lithography. As a result, research topics regarding to photoresist materials applied to the EUV process, defect detection, and mask protective pellicles with enhanced transparency flourish.

The present disclosure generally relates to semiconductor equipment. More particularly, the present disclosure relates to an extreme ultraviolet (EUV) radiation light source generation apparatus.

The feature size of the EUV process can be less than <NUM> nanometer (nm). If a conventional laser of longer wavelength (e.g., <NUM>) or a deep ultraviolet light is used as the detection radiation source, subtle defects on the mask may not be observed. The industry usually uses laser produced plasma (LPP) or discharged produced plasma (DPP) to generate incoherent EUV radiation sources. However, defect detection using incoherent light requires additional optical elements to gather light, reducing optical converting efficiency and also increasing complexity and difficulty of defect detection. The plasma generation process also causes a lot of pollution. <CIT> discloses an extreme ultraviolet light generation system used with a laser apparatus, where the extreme ultraviolet light generation system may include: a chamber including at least one window for at least one laser beam and a target supply unit for supplying a target material into the chamber; and at least one polarization control unit, provided on a laser beam path, for controlling a polarization state of the at least one laser beam. <CIT> discloses a kind of extreme ultraviolet superfast time resolution photoelectricity spectroscopy systems of high repetition frequency, including the high pulse repetition frequency ultra-short pulse laser system amplified based on fiber chirped pulse, extreme ultraviolet ultrashort pulse converting system, optical parameter converting system and ultrashort pulse pump probe photoelectricity spectroscopy systems. <CIT> discloses a method for extending and enhancing bright coherent high-order harmonic generation into the VUV-EUV-X-ray regions of the spectrum involves a way of accomplishing phase matching or effective phase matching of extreme upconversion of laser light at high conversion efficiency, approaching <NUM>-<NUM> in some spectral regions, and at significantly higher photon energies in a waveguide geometry, in a self-guiding geometry, a gas cell, or a loosely focusing geometry, containing nonlinear medium. Tsai Chia-Lun et al. discloses a nonlinear compression of intense optical pulses at <NUM> by multiple plate continuum generation. Intense ultrashort laser pulses at <NUM> are generated by a home-built light source and compressed to <NUM> fs by multiple plate continuum (MPC) and Fourier pulse shaping. The entire system consists of three building blocks, responsible for seed generation, optical parametric chirped pulse amplification (OPCPA), and nonlinear compression. <CIT> discloses control of average wavelength-converted power or pulse energy. Seed pulses may be generated, amplified and wavelength converted. Wavelength-converted power or pulse energy may be controlled by adjusting conversion efficiency without substantially changing amplified power or pulse energy. Average wavelength-converted power may be controlled over a time comparable to an amplified pulse period without adjusting average amplified pulse power over that time. An optical system may comprise a seed source coupled to an optical amplifier, a wavelength converter coupled to the optical amplifier, and a controller coupled to the seed source, optical amplifier or wavelength converter.

The disclosure provides a an extreme-ultraviolet (EUV) radiation. light source generation apparatus including a pump laser, at least one pulse shaping unit, a wavelength conversion unit, and a high-order harmonics generation unit. The pump laser is configured to provide a pulse laser radiation beam. Each one of the at least one pulse shaping unit is configured to conduct a spectrum extending operation and a phase compensation operation to the pulse laser radiation beam, and the phase compensation operation is configured to make a plurality of frequency components of the pulse laser radiation beam emitted by the pulse shaping unit to be substantially in phase. The wavelength conversion unit is configured to conduct a center wavelength conversion operation to the pulse laser radiation beam. The high-order harmonics generation unit is configured to receive the pulse laser radiation beam processed by the at least one pulse shaping unit and the center wavelength conversion operation, and is configured to focus the received pulse laser radiation beam to a high order harmonic generation medium to generate a high order harmonic radiation beam.

The disclosure provides an EUV radiation light source generating method including the following operations: utilizing a pump laser to provide a pulse laser radiation beam to an optical propagation path, wherein the pulse laser radiation beam has a first pulse duration; conducting a center wavelength conversion operation on the optical propagation path, so as to convert a first center wavelength of the pulse laser radiation beam to a second center wavelength, wherein the first center wavelength is different from the second center wavelength; conducting a first spectrum extending operation on the optical propagation path, so as to extend a first bandwidth of the pulse laser radiation beam to a second bandwidth, wherein the first bandwidth is smaller than the second bandwidth; conducting a first phase compensation operation on the optical propagation path, wherein the first phase compensation operation is configured to make a plurality of frequency components of the pulse laser radiation beam having the second bandwidth substantially in phase, the pulse laser radiation beam processed by the first phase compensation operation has a second pulse duration, and the first pulse duration is greater than the second pulse duration; focusing the pulse laser radiation beam, processed by the first spectrum extending operation, the first phase compensation operation, and the center wavelength conversion operation, to a high order harmonic generation medium to generate a high order harmonic radiation beam.

The disclosure provides a defect detection system including an EUV radiation light source generation apparatus and a defect detection apparatus. The EUV radiation light source generation apparatus includes a pump laser, at least one pulse shaping unit, a wavelength conversion unit, and a high-order harmonics generation unit. The pump laser is configured to provide a pulse laser radiation beam. Each one of the at least one pulse shaping unit is configured to conduct a spectrum extending operation and a phase compensation operation to the pulse laser radiation beam, and the phase compensation operation is configured to make a plurality of frequency components of the pulse laser radiation beam emitted by the pulse shaping unit to be substantially in phase. The wavelength conversion unit is configured to conduct a center wavelength conversion operation to the pulse laser radiation beam. The high-order harmonics generation unit is configured to receive the pulse laser radiation beam processed by the at least one pulse shaping unit and the center wavelength conversion operation, and is configured to focus the received pulse laser radiation beam to a high order harmonic generation medium to generate a high order harmonic radiation beam. The defect detection apparatus includes a testing platform, a detection unit, and an analysis unit. The testing platform is configured to set a sample under test, and the high order harmonic radiation beam is configured to be incident to the sample under test by a predetermined angle of incidence. The detection unit is configured to detect a diffraction result of the high order harmonic radiation beam diffracting the sample under test. The analysis unit is electrically coupled to the detection unit, and is configured to construct an image corresponding to the sample under test according to the diffraction result.

It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the disclosure as claimed.

Reference will now be made in detail to the present embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.

Certain terms are used throughout the description and the claims to refer to particular components. One skilled in the art appreciates that a component may be referred to as different names. This disclosure does not intend to distinguish between components that differ in name but not in function. In the description and in the claims, the term "comprise" is used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. " The term "couple" is intended to compass any indirect or direct connection. Accordingly, if this disclosure mentioned that a first device is coupled with a second device, it means that the first device may be directly or indirectly connected to the second device through electrical connections, wireless communications, optical communications, or other signal connections with/without other intermediate devices or connection means.

The term "and/or" may comprise any and all combinations of one or more of the associated listed items. In addition, the singular forms "a," "an," and "the" herein are intended to comprise the plural forms as well, unless the context clearly indicates otherwise.

The extreme ultraviolet (EUV) light recited in this disclosure may comprise electromagnetic radiation having wavelength substantially of <NUM> to <NUM> nanometer (nm).

The exposure wavelength of EUV lithography recited in this disclosure may substantially be <NUM>, or substantially be in the band of EUV having a range of <NUM> plus/minus <NUM> %.

The detection wavelength recited in this disclosure may substantially be <NUM>-<NUM>.

The terms substrate and patterned substrate recited in this disclosure may refer to a non-patterned wafer or a patterned wafer.

The term mask recited in this disclosure may refer to a reticle or a reticle having a pellicle.

Provided herein are explanations in respect of reference labels used in embodiments of this disclosure. The same reference labels are used to refer to the same or like elements, for example, a pulse laser radiation beam received by a continuum unit is having a reference label L, and a pulse laser radiation beam emitted by the continuum unit having a reference label L'. As another example, a pulse laser radiation beam received by the pulse compression unit having a reference label L', and a pulse laser radiation beam emitted by the pulse compression unit having a reference label L".

The pulse laser radiation beam L recited in this disclosure has a bandwidth β, a wavelength λ, and a pulse duration t which are referred to by a corresponding index. For instance, a pulse laser radiation beam L1 has a bandwidth β1, a wavelength λ1, a pulse duration t1. As another instance, a pulse laser radiation beam L2 has a bandwidth β2, a wavelength λ2, and a pulse duration t2, and so forth.

The term bandwidth recited in this disclosure may represent the full width at half maximum (FWHM) of a waveform in frequency domain of a pulse laser.

The term pulse duration recited in this disclosure may represent the full width at half maximum (FWHM) of a waveform in time domain of a pulse laser.

The optical propagation path, recited in this disclosure, of an extreme-ultraviolet (EUV) radiation light source generation apparatus may comprise a plurality of pulse laser radiation beams.

<FIG> is a schematic diagram for illustrating the semiconductor manufacturing process according to one embodiment of the present disclosure. As shown in <FIG>, the semiconductor manufacturing process comprises photoresist coating and EUV lithography. First of all, the substrate <NUM> enters a photosensitive material coating operation (operation S01) so that the photoresist <NUM> is coated on the substrate <NUM>. Then, the substrate <NUM> enters a mask exposing operation of the EUV lithography (operation S02) so as to use the EUV light <NUM> and the mask <NUM> to etch the pattern <NUM> onto the substrate <NUM>. The EUV light <NUM> may be a plasma state light source generated by the laser-produced plasma (LPP) method or the discharge-produced plasma (DPP) method. Since the plasma state light source is incoherent and non-collimated, a great quantity of optical elements (e.g., reflective mirror, filters, light collector, etc.) are required to gather light having center wavelength substantially equal to <NUM>. Furthermore, optical elements has low reflect efficiency of the EUV light source due to characteristics of the EUV light source, and therefore the plasma state EUV light source usually accompanies by great power loss. The minimum feature size of patterns of the EUV lithography is smaller than <NUM>, causing strict requirements toward the design and detect of the patterns on the mask. A slightly defect on the mask, misalignment between the mask and the substrate, and other optical interferences affect the exposing quality of the EUV lithography or the related mask detection quality.

It is worth mentioning that incoherent light source requires more optical elements, causing optical interferences in greater chance during mask detecting so as to affect mask detection quality. Therefore, incoherent light source is not suitable for the at-wavelength optical metrology. High-order harmonics generation (HHG) may be used to generate coherent EUV light, but the coherent EUV light generated by this method has low average intensity. Therefore, this disclosure provides EUV radiation light source generation apparatuses and EUV radiation light source generating methods capable for providing a high power EUV light, and related apparatuses and methods, utilizing the high power EUV light, for performing the at-wavelength optical metrology.

<FIG> is a simplified functional block diagram of a defect detection system <NUM> according to one embodiment of the present disclosure. As shown in <FIG>, the defect detection system <NUM> comprises an EUV radiation light source generation apparatus <NUM> and a defect detection apparatus <NUM>. The EUV radiation light source generation apparatus <NUM> comprises a pump laser <NUM> arranged on an optical propagation path <NUM>, at least one pulse shaping unit (e.g., pulse shaping units 1100A and 1100B), a wavelength conversion unit <NUM>, and a high-order harmonics generation unit <NUM>.

In the situation that the number of the at least one pulse shaping unit is <NUM>, the pulse shaping unit 1100A ( or the pulse shaping unit 1100B) may be arranged between the pump laser <NUM> and the wavelength conversion unit <NUM>, or between the wavelength conversion unit <NUM> and the high-order harmonics generation unit <NUM>. In another situation that the number of the at least one pulse shaping unit is more than <NUM>, the pulse shaping units 1100A and 1100B may be respectively arranged between the pump laser <NUM> and the wavelength conversion unit <NUM> and between the wavelength conversion unit <NUM> and the high-order harmonics generation unit <NUM>.

The pulse shaping units 1100A and 1100B are configured to perform spectrum extending and phase compensation to the pulse laser radiation beam on the optical propagation path <NUM>, thereby reducing the pulse duration of the pulse laser radiation beam to improve the peak intensity of the pulse laser radiation beam. The wavelength conversion unit <NUM> is configured to adjust the center wavelength of the pulse laser radiation beam on the optical propagation path <NUM>. The high-order harmonics generation unit <NUM> is configured to receive the pulse laser radiation beam whose peak intensity and center wavelength has been adjusted, and configured to generate, according to the received pulse laser radiation beam, high power EUV light suitable for mask detection. The defect detection apparatus <NUM> is configured to receive EUV light from the high-order harmonics generation unit <NUM>, and configured to detect the sample under test <NUM> by using the EUV light. The number and location of the pulse shaping unit may be determined in accordance with practical design requirements, which will be described in the following paragraphs.

In some embodiments, the pump laser <NUM> may be realized by Yb:YAG laser or the Ti:sapphire laser. In one embodiment, the pump laser <NUM> comprising the Yb:YAG has an output wavelength of <NUM> and a pulse duration of <NUM> femtosecond (fs). In one embodiment, the pump laser <NUM> comprising the Ti:sapphire has an output wavelength of <NUM> and a pulse duration of <NUM> femtosecond (fs), but this disclosure is not limited thereto. Notably, the laser gain medium of the pump laser <NUM> may be selected according to the repetition rate and the peak intensity of the pump laser <NUM> so that the average intensity of the pump laser <NUM> is substantially greater than <NUM> watt (W). In one embodiment, the repetition rate of the pump laser <NUM> is substantially from <NUM> to <NUM>. In addition, additional optical elements may be arranged, according to practical design requirements, between any two components of the defect detection system <NUM>, in order to change optical propagation path <NUM> or to focus the pulse laser radiation beam. For example, optical elements such as lens, concave mirror, parabolic mirror, and reflective mirror may be used, but this disclosure is not limited thereto.

It worth mentioning that the high-order harmonics generation unit <NUM> comprises the gas transmission unit <NUM> and the gas cell <NUM>. The gas transmission unit <NUM> is configured to provide the high order harmonic generation medium (e.g., inert gas target material) into the gas cell <NUM>, and the high-order harmonics generation unit <NUM> focuses the received pulse laser radiation beam to the high order harmonic generation medium in the gas cell <NUM>. Operation of the high-order harmonics generation unit <NUM> will be further described in the following paragraphs.

In one embodiment, the high-order harmonics generation unit <NUM> and the defect detection apparatus <NUM> is operated in a vacuum environment.

In another embodiment, the EUV radiation light source generation apparatus <NUM> further comprises a filtering unit FT. The filtering unit FT is configured to filter EUV light of certain wavelengths and infrared light in the pulse laser radiation beam generated by the high-order harmonics generation unit <NUM>, and configured to preserve EUV light having specific wavelengths (e.g., <NUM>). In practice, the filtering unit FT may be realized by the metallic film, high reflective multilayer mirror for specific light wavelengths, or a combination of spectrometer and aperture.

<FIG> is a simplified functional block diagram of an EUV radiation light source generation apparatus <NUM> according to one embodiment of the present disclosure. The EUV radiation light source generation apparatus <NUM> of <FIG> may be used to realize the EUV radiation light source generation apparatus <NUM> of <FIG>. As shown in <FIG>, the EUV radiation light source generation apparatus <NUM> comprises a pump laser <NUM>, a pulse shaping unit 1100A, a wavelength conversion unit <NUM>, and high-order harmonics generation unit <NUM> which are arranged in sequence on a light transmission path of the EUV radiation light source generation apparatus <NUM>, wherein the pulse shaping unit 1100A comprises continuum unit 1110A and pulse compression unit 1112A. For the sake of brevity, part of the light transmission path of the EUV radiation light source generation apparatus <NUM> is omitted in <FIG>.

In this embodiment, the pump laser <NUM> is configured to generate a pulse laser radiation beam L1 having a center wavelength λ1, a bandwidth β1, and a pulse duration t1. The continuum unit 1110A is configured to receive the pulse laser radiation beam L1, and to emit a pulse laser radiation beam L1' having a bandwidth β1' greater than bandwidth β1. The pulse compression unit 1112A is configured to receive the pulse laser radiation beam L1', and to emit a pulse laser radiation beam L1" having a pulse duration t1" smaller than the pulse duration of the pulse laser radiation beam L1'. The wavelength conversion unit <NUM> is configured to receive the pulse laser radiation beam L1", and to emit the pulse laser radiation beam L2 having a center wavelength λ2 larger than or smaller than the center wavelength λ1. The high-order harmonics generation unit <NUM> is configured to receive the pulse laser radiation beam L2, and to generate a pulse laser radiation beam LHHG reaching specific electron volts (eV) (e.g., <NUM> eV) by using the pulse laser radiation beam L2.

In one embodiment, the center wavelength λ1 of the pulse laser radiation beam L1 may be <NUM>, and the pulse duration t1 may be approximately in a range of <NUM> fs to <NUM> picoseconds (ps), but this disclosure is not limited thereto. It should be understood that any other suitable types of pump laser <NUM> may be used as will be apparent to those of ordinary skill in the art in view of the teachings herein.

<FIG> is a simplified functional block diagram of an EUV radiation light source generation apparatus <NUM> according to one embodiment of the present disclosure. As shown in <FIG>, the EUV radiation light source generation apparatus <NUM> comprises a pump laser <NUM>, a wavelength conversion unit <NUM>, a pulse shaping unit 1100A, and a high-order harmonics generation unit <NUM> arranged in sequence on an optical propagation path of the EUV radiation light source generation apparatus <NUM>, that is, the wavelength conversion unit <NUM> is arranged between the pulse shaping unit 1100A and the pump laser <NUM>.

The pump laser <NUM> is configured to generate the pulse laser radiation beam L1 having the center wavelength λ1, the bandwidth β1, and the pulse duration t1. The wavelength conversion unit <NUM> is configured to receive the pulse laser radiation beam L1, and configured to emit the pulse laser radiation beam L2 having the center wavelength λ2, the pulse duration t2, and the bandwidth β2, in the event that the center wavelength λ2 may be larger than or smaller than the center wavelength λ1. The continuum unit 1110A is configured to receive the pulse laser radiation beam L2, and configured to emit the pulse laser radiation beam L2' having the bandwidth β2', in the event that the bandwidth β2' is greater than the bandwidth β2 and the pulse duration of the pulse laser radiation beam L2' is smaller than the pulse duration t2. The pulse compression unit 1112A is configured to receive the pulse laser radiation beam L2' emitted by the continuum unit 1110A, and emit the pulse laser radiation beam L2" having the pulse duration t2", in the event that the pulse duration t2" is smaller than the pulse duration of the pulse laser radiation beam L2'. The high-order harmonics generation unit <NUM> is configured to receive the pulse laser radiation beam L2", and configured to emit the pulse laser radiation beam LHHG reaching specific electron volts according to the pulse laser radiation beam L2".

<FIG> is a simplified functional block diagram of an EUV radiation light source generation apparatus <NUM> according to one embodiment of the present disclosure. The EUV radiation light source generation apparatus <NUM> of <FIG> is similar to the EUV radiation light source generation apparatus <NUM> of <FIG>, the difference is that the EUV radiation light source generation apparatus <NUM> of <FIG> further comprises a pulse shaping unit 1100B. The pulse shaping unit 1100B is arranged on the light transmission path of the EUV radiation light source generation apparatus <NUM>, and is located between the wavelength conversion unit <NUM> and the high-order harmonics generation unit <NUM>. The pulse shaping unit 1100B comprises a continuum unit 1110B and a pulse compression unit 1112B. The continuum unit 1110B is configured to receive the pulse laser radiation beam L2 emitted by the wavelength conversion unit <NUM>, and configured to emit the pulse laser radiation beam L2' having the bandwidth β2'. The bandwidth β2' of the pulse laser radiation beam L2' is larger than the bandwidth β2 of the pulse laser radiation beam L2, and the pulse duration of the pulse laser radiation beam L2' is smaller than the pulse duration t2 of the pulse laser radiation beam L2.

The foregoing descriptions regarding the implementations, connections, operations, and related advantages of other corresponding functional blocks in the EUV radiation light source generation apparatus <NUM> are also applicable to the EUV radiation light source generation apparatus <NUM>. For the sake of brevity, those descriptions will not be repeated here.

<FIG> is a simplified functional block diagram of an EUV radiation light source generation apparatus <NUM> according to one embodiment of the present disclosure. The EUV radiation light source generation apparatus <NUM> of <FIG> is similar to the EUV radiation light source generation apparatus <NUM> of <FIG>, the difference is that the EUV radiation light source generation apparatus <NUM> of <FIG> further comprises a pulse shaping unit 1100C. The pulse shaping unit 1100C is arranged on the light transmission path of the EUV radiation light source generation apparatus <NUM>, and is located between the pulse shaping unit 1100A and the high-order harmonics generation unit <NUM>. The pulse shaping unit 1100C comprises a continuum unit 1110C and a pulse compression unit 1112C. The continuum unit 1110C is configured to receive the pulse laser radiation beam L2" emitted by the pulse compression unit 1112A, and configured to emit the pulse laser radiation beam L21. The bandwidth of the pulse laser radiation beam L21 is larger than the bandwidth β2" of the pulse laser radiation beam L2", and the pulse duration of the pulse laser radiation beam L21 is smaller than the pulse duration t2" of the pulse laser radiation beam L2".

As can be appreciated from the forgoing descriptions, the EUV radiation light source generation apparatuses in this disclosure feature the adjustments to the pulse laser radiation beam being inputted to the high-order harmonics generation unit <NUM>. By adjusting the center wavelength, the pulse waveform in time domain, and the pulse duration of the pulse laser radiation beam being inputted to the high-order harmonics generation unit <NUM>, the high-order harmonics generation unit <NUM> is capable of emitting the pulse laser radiation beam reaching the specific electron volts.

For the EUV radiation light source generation apparatuses in this disclosure, the pulse laser radiation beam being inputted to the high-order harmonics generation unit <NUM> may have the pulse duration, in time domain, at the picosecond level or at the femtosecond level.

For the EUV radiation light source generation apparatuses in this disclosure, the pulse laser radiation beam thereof reaching the specific electron volts may have the power at the nanowatt (nW) level to the watt (W) level.

The following paragraphs provide specific implementations respectively for the components comprised by the EUV radiation light source generation apparatuses in this disclosure. <FIG> is a schematic diagram of a continuum unit <NUM> according to one embodiment of the present disclosure. <FIG> is a schematic diagram of a continuum unit <NUM> according to another embodiment of the present disclosure. <FIG> is a schematic diagram for illustrating the compressing ratio of the continuum unit of <FIG>. <FIG> is a schematic diagram of a continuum unit <NUM> according to yet another embodiment of the present disclosure. The continuum units 1110A, 1110B, and 1110C each can be realized by the continuum unit <NUM>, <NUM>, or <NUM>. For ease of understanding, the following embodiments will be described respectively with reference to <FIG>, and also to the continuum unit 1110A of <FIG> as an example.

Continuum units in this disclosure use the nonlinear effect of the pulse laser radiation beam passing through different mediums, preferably the third-order nonlinear effect, so that the spectrum of the pulse laser radiation beam is extended. Reference is first made to <FIG>, the continuum unit <NUM> comprises a plurality of condensed state transparent plates <NUM>-<NUM> ~ <NUM>-n, and is configured to receive the corresponding pulse laser radiation beam L1, and is further configured to emit the corresponding pulse laser radiation beam L1'. The condensed state transparent plates <NUM>-<NUM> ~ <NUM>-n are arranged in sequence on the light transmission path of the pulse laser radiation beam L1. An angle between the light transmission path and an incident surface of each of the condensed state transparent plates <NUM>-<NUM> ~ <NUM>-n may be the Brewster's angle. The spacings, between every two central points of respective two adjacent condensed state transparent plates, are configured to decrease in sequence. For instance, the central point of the condensed state transparent plate <NUM>-<NUM> and the central point of the condensed state transparent plate <NUM>-<NUM> are spaced by a predetermined distance D1; the central point of the condensed state transparent plate <NUM>-<NUM> and the central point of the condensed state transparent plate <NUM>-<NUM> are spaced by a predetermined distance D2; the central point of the condensed state transparent plate <NUM>-<NUM> and the central point of the condensed state transparent plate <NUM>-<NUM> are spaced by a predetermined distance D3, in the event that the predetermined distance D1 is greater than the predetermined distance D2 and the predetermined distance D2 is larger than the predetermined distance D3, and so on.

The continuum unit <NUM> causes a widened bandwidth because of a plurality of times of third-order nonlinear effect induced by the condensed state transparent plates <NUM>-<NUM> ~ <NUM>-n, but the bandwidth, the continuum unit <NUM> may extend, gradually becomes saturated when the number of the condensed state transparent plates <NUM>-<NUM> ~ <NUM>-n increases. This is because of the material characteristics of the condensed state transparent plates <NUM>-<NUM> ~ <NUM>-n, and also because of the pulse laser radiation beam L1 gradually diverged with the increasement of the number of the condensed state transparent plates <NUM>-<NUM> ~ <NUM>-n. Therefore, to configure the continuum unit <NUM> for providing the maximum bandwidth in the most efficiency means, the condensed state transparent plates <NUM>-<NUM> ~ <NUM>-n may be adjusted in number, relative positions, and/or thickness as will be apparent to those of ordinary skill in the art in view of the teachings herein.

The thickness of the aforesaid condensed state transparent plate relates to the self-focusing characteristic thereof, since the intensity gradient of the pulse laser radiation beam, in the cross-section view, is spatially distributed. The pulse laser radiation beam is focused when passing through the condensed state transparent plate, and is diverged, after self focusing on the light transmission path, when passing through air. Therefore, the pulse laser radiation beam repeatedly self focuses and diverges according to the condensed state transparent plate through which the pulse laser radiation beam passes. Therefore, the thickness of the condensed state transparent plate may be determined in accordance with the intensity of the pulse laser radiation beam and the characteristics of the condensed state transparent plate. In one embodiment, the focal spot of the self-focusing effect of the condensed state transparent plate is external to the condensed state transparent plate.

In another embodiment, the continuum unit <NUM> comprises a plurality of condensed state transparent plates each having the anti-reflection film (not shown). The plurality of condensed state transparent plates having the anti-reflection film are arranged in sequence on the light transmission path of the pulse laser radiation beam L1, and the incident surfaces of the condensed state transparent plates may be in parallel to each other.

Reference is made to <FIG>, the continuum unit <NUM> comprises a hollow core fiber <NUM> so as to extend spectrum by using the third-order nonlinear effect of the pulse laser radiation beam passing through the inert gas in the hollow core fiber <NUM>. The nonlinear effect induced by the gaseous medium relates to the length of a hollow core fiber. In general, a hollow core fiber of a longer length induces a higher nonlinear phase shift of the accumulated third-order nonlinear effect, thereby obtaining a more significant extended spectrum effect. <FIG> is a schematic diagram of the pulse duration of the pulse laser radiation beam passed through the continuum unit <NUM>. Curve <NUM> represents the pulse laser radiation beam L1, which has not yet passed through the continuum unit <NUM>, having a pulse duration WA of approximately <NUM> fs. Curve <NUM> represents the pulse laser radiation beam L1', which passed through the continuum unit <NUM>, having a pulse duration WB of approximately <NUM> fs. Therefore, the compressing ratio of the hollow core fiber <NUM> is substantially <NUM>:<NUM> to <NUM>:<NUM> in this embodiment.

Reference is made to <FIG>, the continuum unit <NUM> may be realized by a multipass cell, wherein the multipass cell comprising a reflective mirror <NUM>, a reflective mirror <NUM>, and a medium <NUM> having nonlinear effect. The continuum unit <NUM> is configured to extend spectrum by using the third-order nonlinear effect caused by the pulse laser radiation beam passing through the medium <NUM> in the continuum unit <NUM> for multiple times. Notably, the pulse laser radiation beam L1 is a pulse laser radiation beam that has not yet passed through the continuum unit <NUM>, while the pulse laser radiation beam L1' is a pulse laser radiation beam that passed through the continuum unit <NUM>.

Other materials, such as the photonic crystal fiber, the high nonlinear fiber, and the bulk crystal like sapphire, can also be used to extend spectrum, the extended spectrum material of the continuum unit can be decided according to the energy of the received pulse laser radiation beam and also to the width of the spectrum to be extended, and this disclosure is not limited to the above materials. Other embodiments of the invention which generates the high power EUV light source by the selection of the wavelength of the pump laser and by the usage the continuum unit will be apparent to those of ordinary skill in the art in view of the teachings herein.

<FIG> is a simplified waveform schematic of the pulse laser radiation beam L1 inputted to the continuum unit <NUM> according to one embodiment of the present disclosure. <FIG> is a simplified waveform schematic diagram of the pulse laser radiation beam L1' emitted by the continuum unit <NUM> according to one embodiment of the present disclosure. Reference is first made to <FIG>, the envelope of the pulse laser radiation beam L1 inputted to the continuum unit <NUM> is indicated by dotted lines, while the carrier signal of the pulse laser radiation beam L1 is indicated by a solid line. Reference is made to <FIG>, the envelope of the pulse laser radiation beam L1' is indicated by dotted lines, while the carrier signal of the pulse laser radiation beam L1' is indicated by a solid line.

As can be appreciated from <FIG>, the carrier frequencies of the pulse laser radiation beam L1 and the pulse laser radiation beam L1' is substantially equal, but difference frequency components of the pulse laser radiation beam L1 are in phase in the frequency domain. As shown in <FIG>, the pulse laser radiation beam L1' passed through the continuum unit <NUM> has a widened bandwidth, and there are phase difference between the higher-frequency components and the lower-frequency components of the pulse laser radiation beam L1'.

Reference is made to <FIG>, to eliminate the spectral phase difference, the pulse laser radiation beam L1' is further inputted to the pulse compression unit 1112A so that different frequency components of the pulse laser radiation beam L1' is adjusted, by phase compensation, to be substantially in phase. As a result, owing to constructive interference of different frequency components, the pulse laser radiation beam L1" emitted by the pulse compression unit 1112A has the time domain pulse duration more narrow than that of the pulse laser radiation beam L1 and the pulse laser radiation beam L1'.

In one embodiment, a ratio of the pulse duration of the pulse laser radiation beam L1 to that of the pulse laser radiation beam L1" may be up to <NUM>, but this disclosure is not limited thereto. The ratio of the pulse duration of the pulse laser radiation beam L1 to that of the pulse laser radiation beam L1" may be adjusted according to practical design requirements.

Additionally, reference is made to <FIG>, since the EUV radiation light source generation apparatus <NUM> comprises two continuum units 1110A ~ 1110B and two pulse compression units 1112A ~ 1112B, the ratio of the pulse duration of the pulse laser radiation beam L1 to that of the pulse laser radiation beam L2" may be up to <NUM> in the EUV radiation light source generation apparatus <NUM>. In one embodiment, the ratio of the pulse duration of the pulse laser radiation beam L1 to that of the pulse laser radiation beam L2" is in a range of <NUM>:<NUM> to <NUM>:<NUM>.

In one embodiment, for example, the center wavelength λ1, the bandwidth β1, and the pulse duration t1 of the pulse laser radiation beam L1 of the EUV radiation light source generation apparatus <NUM> may be substantially <NUM>, <NUM>, and <NUM> fs, respectively. The pulse duration t2" of the pulse laser radiation beam L2" may be substantially equal to or lower than <NUM> fs.

<FIG> is a schematic diagram of a pulse compression unit <NUM> according to one embodiment of the present disclosure. The pulse compression unit <NUM> may be used to realize the pulse compression units 1112A, 1112B, and 1112C in the aforementioned embodiments, and comprises chirped mirrors <NUM> and <NUM> arranged substantially in parallel to each other. Each of the chirped mirrors <NUM> and <NUM> may be realized by comprising a plurality of coating layers. For the purpose of explanation convenience, only two chirped mirrors are shown in <FIG>, but this disclosure is not limited thereto. In some embodiments, the number of the chirped mirrors may be decided according to the practical design requirements.

For ease of understanding, <FIG> will be explained with the pulse compression unit 1112A of <FIG>. As shown in <FIG>, the pulse compression unit <NUM> is configured to receive the corresponding pulse laser radiation beam L1'. The pulse laser radiation beam L1' comprises difference frequency components that are not in phase, and each coating layer of the chirped mirrors <NUM> and <NUM> is configured to reflect a corresponding one of the difference frequency components. The difference frequency components will be rendered substantially in phase after being reflected for multiple times. In other words, the pulse laser radiation beam L1" emitted by the pulse compression unit <NUM> comprises difference frequency components that are substantially in phase.

<FIG> is a schematic diagram of a pulse compression unit <NUM> according to one embodiment of the present disclosure. The pulse compression unit <NUM> comprises a diffraction unit <NUM>, a diffraction unit <NUM>, and a liquid crystal pixel matrix <NUM>. For the purpose of explanation convenience, only two diffraction units <NUM> and <NUM> are shown in <FIG>, but this disclosure is not limited thereto. In some embodiment, the number of the diffraction unit may be decided according to the practical design requirements. In one embodiment, the diffraction unit may be realized by the grating.

For ease of understanding, <FIG> will be explained with the pulse compression unit 1112A of <FIG>. As shown in <FIG>, when the pulse compression unit <NUM> receives the pulse laser radiation beam L1', the diffraction unit <NUM> and the diffraction unit <NUM> are configured to adjust the light transmission path of the pulse laser radiation beam L1' so that the pulse laser radiation beam L1' is incident into the liquid crystal pixel matrix <NUM>. The liquid crystal pixel matrix <NUM> may control the twist angle of the liquid crystal for different sections independently. As a result, different frequency components that have passed the liquid crystal pixel matrix <NUM> have phases unrelated to frequencies so that the spatial light modulation is achieved.

In some embodiments, the pulse compression unit may also be realized by a combination of the grating pair and other optical elements (e.g., the lens or the reflective mirror), but this disclosure is not limited thereto. It should be understood that any other suitable means of pulse duration compression technology for the pulse laser radiation beam may be used as will be apparent to those of ordinary skill in the art in view of the teachings herein.

In another embodiment, the pulse compression unit not only adjusts, by phase compensation, the amplitude of the pulse laser radiation beam in time domain, but also adjusts other characteristics of the pulse laser radiation beam. Reference is again made to <FIG>, for example, the liquid crystal pixel matrix <NUM> may adjust the luminance of the pulse laser radiation beam in time domain by control the twist angle of the liquid crystal for different sections independently in time. As a result, the time light modulation is achieved.

In addition, the pulse compression unit adjusts characteristics in a wider degree when the bandwidth of the inputted pulse laser radiation beam increases. Therefore, in some embodiments, the continuum unit is arranged in front of the pulse compression unit so that the pulse compression unit receives a pulse laser radiation beam of a bandwidth as wide as possible.

Reference is made again to <FIG>, the wavelength conversion unit <NUM> in this disclosure may comprise a nonlinear optical crystals which is configured to convert the center wavelength λ1 of the pulse laser radiation beam L1, thereby emitting a pulse laser radiation beam L2 having the center wavelength λ2 and the bandwidth β2, wherein the center wavelength λ1 may be different from the center wavelength λ2. In one embodiment, the wavelength conversion unit <NUM> is realized by the frequency-doubling crystal. Therefore, the wavelength λ2 is n times of the wavelength λ1, and n is an integer.

The acceptance bandwidth of the wavelength conversion unit <NUM> may be a sinc square function. Therefore, the maximum input bandwidth of the wavelength conversion unit <NUM> is related to the acceptance bandwidth thereof. If the pulse laser radiation beam incident into the wavelength conversion unit <NUM> having a bandwidth wider than the acceptance bandwidth of the wavelength conversion unit <NUM>, the converting efficiency of the wavelength conversion unit <NUM> may decrease. Therefore, as shown in <FIG> and <FIG>, the wavelength conversion unit <NUM> may be arranged between the pump laser <NUM> and the continuum unit 1110A so that the wavelength conversion unit <NUM> has an improved converting efficiency.

In addition, reference is made to <FIG>, the wavelength conversion unit <NUM> is arranged between the continuum unit 1110A and the continuum unit 1110B, in order to prevent the wavelength conversion unit <NUM> from receiving a pulse laser radiation beam having an excessively wide bandwidth caused by twice spectrum extending operation. As a result, not only the adjustability of the pulse laser radiation beam LHHG is increased but also the converting efficiency of the wavelength conversion unit <NUM> is ensured.

The aforementioned non-linear optical crystal may comprise materials configured to realize nonlinear optical processes, for example, the second-harmonics generation (SHG), the third-harmonics generation (THG), the optical parametric oscillator (OPO), the optical parametric amplification (OPA), the self-phase modulation (SPM), the optical parametric chirped-pulse amplification (OPCPA), the sum-frequency generation (SFG), the difference-frequency generation (DFG), etc. It should be understood that any other suitable means of frequency conversion for the pulse laser radiation beam may be used as will be apparent to those of ordinary skill in the art in view of the teachings herein.

<FIG> is a simplified functional block diagram of a high-order harmonics generation unit <NUM> of <FIG> according to one embodiment of the present disclosure. <FIG> is a schematic diagram for illustrating electron behavior of the high-order harmonics generation unit <NUM> according to one embodiment of the present disclosure. As shown in <FIG>, the high-order harmonics generation unit <NUM> comprises a gas transmission unit <NUM> and a gas cell <NUM>, and is configured to receive the high order harmonic generation source HLS. The high order harmonic generation source HLS may be the pulse laser radiation beam received by the high-order harmonics generation unit <NUM>, such as the pulse laser radiation beam L2 of <FIG>, the pulse laser radiation beam L2" of <FIG>, the pulse laser radiation beam L2" of <FIG>, and the pulse laser radiation beam L21' of <FIG>.

The gas transmission unit <NUM> is configured to provide the high order harmonic generation medium Gm to the gas cell <NUM>. The high-order harmonics generation unit <NUM> focuses the high order harmonic generation source HLS to the high order harmonic generation medium Gm in the gas cell <NUM>. In some embodiments, the high order harmonic generation medium Gm may be realized by the inert gas such as helium (He), neon (Ne), argon (Ar), krypton (Kr), or xenon (Xe). In some embodiments, in the situation that the pulse duration of the high order harmonic generation source HLS is approximately <NUM> to <NUM> fs, when the high order harmonic generation source HLS has a center wavelength of <NUM>, one of ordinary skill in the art may select argon with air pressure adjustment to obtain the pulse laser radiation beam LHHG having preferable intensity and a center wavelength of <NUM>. In some embodiments, when the high order harmonic generation source HLS has a center wavelength of <NUM>, one of ordinary skill in the art may select helium with air pressure adjustment to obtain the pulse laser radiation beam LHHG having preferable intensity and a center wavelength of <NUM>, but this disclosure is not limited thereto. In some embodiments, type of gas, gas pressure, center wavelength, pulse duration, and location of focal point may be adjusted according to practical requirements.

Reference is made to <FIG>, the high order harmonic generation source HLS focused to the high order harmonic generation medium Gm renders the bound electros of the high order harmonic generation medium Gm, which are at the ground state, to be ionized and therefore becomes free electrons Ef. The free electrons gain kinetic energy because of being accelerated during the ionization process. As the electronic field of the high order harmonic generation source HLS being reversed, part of the free electrons Ef recombine with the atoms AT of the high order harmonic generation medium Gm during the process of backing to ground state. Therefore, the pulse laser radiation beam LHHG having specific center wavelength (i.e., reaching specific electron volts) is emitted.

In one embodiment, the pulse laser radiation beam LHHG emitted by the high-order harmonics generation unit <NUM> reaches electron volts substantially equal to <NUM> eV and has the center wavelength of <NUM>.

In another embodiment, the pulse laser radiation beam LHHG emitted by the high-order harmonics generation unit <NUM> reaches electron volts substantially equal to <NUM> eV and has the center wavelength of <NUM>.

In some embodiments, the pulse laser radiation beam LHHG emitted by the high-order harmonics generation unit <NUM> is of the spectrum in a range of EUV light and soft x-ray, and the pulse laser radiation beam LHHG is absorbable to the atmosphere environment. Therefore, the high-order harmonics generation unit <NUM> needs to be operated in a vacuum environment.

<FIG> is a schematic diagram of the emission spectrum of the pulse laser radiation beam LHHG emitted by the high-order harmonics generation unit <NUM> according to one embodiment of the present disclosure. As shown in <FIG>, the emission spectrum comprises a plurality of pulse laser radiation beams having energy of different harmonic orders, wherein the X-axis is the electron volt (i.e., the photon energy) and the Y-axis is the normalized spectral intensity. The spectral line width of energy of each harmonic order becomes wider when the electron volt increases; the distance of energy between harmonic orders is also slightly increases when the electron volt increases. A larger electron volt corresponds to a shorter wavelength, for example, <NUM> eV corresponds to <NUM> wavelength. Notably, since the cut-off wavelength of the pulse laser radiation beam LHHG (i.e., the wavelength corresponding to the energy of the highest harmonic order) may be correlated to the center wavelength of the pulse laser radiation beam inputted to the high-order harmonics generation unit <NUM>. As a result, an expected cut-off wavelength may be obtained by adjusting the center wavelength and the pulse duration of the pulse laser radiation beam inputted to the high-order harmonics generation unit <NUM>.

In specific, the larger the center wavelength of the pulse laser radiation beam and the smaller the pulse duration of the pulse laser radiation beam inputted to the high-order harmonics generation unit <NUM>, the larger the cut-off energy of the pulse laser radiation beam LHHG, and the smaller the cut-off wavelength of the pulse laser radiation beam LHHG.

For example, <FIG> is a schematic diagram of the emission spectrum generated by using the high-order harmonics generation unit <NUM> to process the pulse laser radiation beam having un-adjusted wavelength and un-adjusted pulse duration. <FIG> is a schematic diagram of the emission spectrum generated by using the high-order harmonics generation unit <NUM> to process the pulse laser radiation beam having adjusted pulse duration. <FIG> is a schematic diagram of the emission spectrum generated by using the high-order harmonics generation unit <NUM> to process the pulse laser radiation beam having adjusted wavelength and adjusted pulse duration. Take <FIG> as an example, the harmonic order energies thereof are mostly smaller than <NUM> eV, and thereof the corresponding wavelength thereof is approximately longer than <NUM>. Take <FIG> as another example, the different harmonic order energies are mostly smaller than <NUM> eV, that is, the corresponding wavelength thereof is approximately longer than <NUM>. Take <FIG> as yet another example, the different harmonic order energies are mostly in a range of <NUM> to <NUM> eV, that is, the corresponding wavelength thereof is in a range of approximately <NUM> to <NUM>.

In other words, by applying spectrum extending and center wavelength adjustment to the pulse laser radiation beam inputted to the high-order harmonics generation unit <NUM>, the emission spectrum of the high-order harmonics generation unit <NUM> is moved to a region corresponding to shorter wavelength. As a result, the spectral intensity of a high-order harmonic pulse laser radiation beam, which reaches a specific electron volt, may be adjusted according to practical requirements.

In general, it is preferable that the spectral intensity of the pulse laser radiation beam emitted by the high-order harmonics generation unit <NUM>, which reaches the specific electron volt, to be greater. In one embodiment, the pulse laser radiation beam reaching the specific electron volt may be configured to be in phase by controlling the ratio of the ground state atoms to the excited state ions of the high order harmonic generation medium. As a result, the spectral intensity of the pulse laser radiation beam reaching the specific electron volt increases because of the constructive interference.

In another embodiment, the gas transmission unit <NUM> of <FIG> is configured to control the air pressure of the high order harmonic generation medium Gm, that is, the gas transmission unit <NUM> may adjust the concentration of the gas configured to be the high order harmonic generation medium Gm. As a result, the pulse laser radiation beam reaching the specific electron volt is in phase to induce constructive interference, thereby increasing spectral intensity, but this disclosure is not limited thereto. It should be understood that any other suitable means of phase matching technology may be used as will be apparent to those of ordinary skill in the art in view of the teachings herein.

In another embodiment, the EUV radiation light source generation apparatus further comprises a band pass filter. The band pass filter is configured to pass the pulse laser radiation beam having a specific level of energy, but filter the pulse laser radiation beam having other levels of electron energy, but this disclosure is not limited thereto. It should be understood that any other suitable means of optical filtering technology may be used as will be apparent to those of ordinary skill in the art in view of the teachings herein.

<FIG> is a flowchart of an EUV radiation light source generating method <NUM> according to one embodiment of the present disclosure. The EUV radiation light source generating method <NUM> comprises the following operations:.

Operation S7100: rendering the pulse laser radiation beam L1 to be incident to a light transmission path, wherein the pulse laser radiation beam L1 has a center wavelength λ1, a bandwidth β1, and a pulse duration t1;.

Operating S7200: converting the center wavelength λ1 of the pulse laser radiation beam L1 on the light transmission path to generate the pulse laser radiation beam L2, wherein the pulse laser radiation beam L2 has the center wavelength λ2, the bandwidth β2, and the pulse duration t2;.

Operation S7300: extending the bandwidth β2 of the pulse laser radiation beam L2 on the light transmission path to generate the pulse laser radiation beam L2', wherein the pulse laser radiation beam L2' has the bandwidth β2'. The spectrum of the pulse laser radiation beam L2' is the supercontinuum spectrum, and the bandwidth β2' is larger than the bandwidth β1 and the bandwidth β2;.

Operation S7400: compensating the phase of the pulse laser radiation beam L2' on the light transmission path to generate the pulse laser radiation beam L2", wherein the pulse laser radiation beam L2" having a pulse duration t2" smaller than the pulse duration of the pulse laser radiation beam L2';.

Operation S7500: focusing the pulse laser radiation beam L2" to high order harmonic generation medium Gm to emit a high-order harmonic pulse laser radiation beam LHHG, wherein the high-order harmonic pulse laser radiation beam comprises radiations reaching a specific electron volt (e.g., <NUM> eV).

<FIG> is a flowchart of an EUV radiation light source generating method <NUM> according to one embodiment of the present disclosure. The EUV radiation light source generating method <NUM> is similar to the EUV radiation light source generating method <NUM> of <FIG>, the different is that the EUV radiation light source generating method <NUM> further comprises the following operations:.

<FIG> is a schematic diagram of a defect detection apparatus <NUM> according to one embodiment of the present disclosure. The defect detection apparatus <NUM> of <FIG> may be used to realize the defect detection apparatus <NUM> of <FIG>. The defect detection apparatus <NUM> comprises a testing platform <NUM>, a detection unit <NUM>, and an analysis unit <NUM>. The testing platform <NUM> is configured to set a sample under test <NUM>. In some embodiments, the sample under test <NUM> may be the mask blank, the patterned mask, or the exposed patterned substrate (e.g., a wafer), but this disclosure is not limited thereto. It should be understood that any other types of sample under test suitable for at-wavelength optical metrology using EUV pulse laser radiation beam may be used as will be apparent to those of ordinary skill in the art in view of the teachings herein. In addition, the detection unit <NUM> may be realized by the charge-coupled device (CCD) or a CMOS based sensor.

The defect detection apparatus <NUM> is configured to use a high order harmonic radiation beam <NUM> having a specific electron volt. The high order harmonic radiation beam <NUM> may be the pulse laser radiation beam LHHG emitted by the high-order harmonics generation unit <NUM> in the aforesaid embodiments. In other words, the high order harmonic radiation beam <NUM> is coherent light, and thus the defect detection apparatus <NUM> is suitable for a defect detection method that is diffraction based and using coherent light.

The defect detection apparatus <NUM> renders the high order harmonic radiation beam <NUM> to be incident to the sample under test <NUM> by a specific angle of incidence θ. In one embodiment, the angle of incidence θ may be substantially equal to an angle which is used during exposure, for example, <NUM> degrees, but this disclosure is not limited thereto. The high order harmonic radiation beam <NUM> reflected by the sample under test <NUM> forms a reflected radiation beam <NUM> comprising information of the sample under test <NUM>. The detection unit <NUM> is configured to gather the reflected radiation beam <NUM> to obtain a diffraction result of the high order harmonic radiation beam <NUM> diffracting the sample under test <NUM>. The detection unit <NUM> is further configured to transmit the diffraction result to the analysis unit <NUM> by wire or wireless transmission so that the analysis unit <NUM> is configured to construct an image of the sample under test <NUM> according to the diffraction result.

In this embodiment, no reflecting-type or transmission-type focusing optical unit is needed for the process which the reflected radiation beam <NUM> is incident into the detection unit <NUM>. Therefore, the defect detection apparatus <NUM> prevents the reflected radiation beam <NUM> from power loss to improve the inspection accuracy and throughout, and the total system complexity is also decreased. The analysis unit <NUM> may use the coherent diffraction imaging method to construct, according to the non-focused reflected radiation beam <NUM>, the image of the sample under test <NUM>.

<FIG> is a schematic diagram of a defect detection apparatus <NUM> according to another embodiment of the present disclosure. The defect detection apparatus <NUM> of <FIG> may be used to realize the defect detection apparatus <NUM> of <FIG> and is similar to the defect detection apparatus <NUM> of <FIG>, the difference is that the defect detection apparatus <NUM> of <FIG> further comprises a focusing optical unit <NUM>. The focusing optical unit <NUM> is a reflecting-type or transmission-type optical element. The specific defect detection method is similar to or the same as the previous embodiment and those descriptions will not be repeated herein for the sake of brevity. Compared to the previous embodiment, the focusing optical unit <NUM> in this embodiment is capable of focusing the light beams comprising the information of the sample under test <NUM>, thereby obtaining a more accurate analyzing result.

In specific, the reflected radiation beam <NUM> that has been focused by the focusing optical unit <NUM> forms the focused radiation beam <NUM> comprising information of the sample under test <NUM>. The detection unit <NUM> gathers the focused radiation beam <NUM> to obtain the diffraction result of the high order harmonic radiation beam <NUM> diffracting the sample under test <NUM>. The detection unit <NUM> further transmits the diffracting result to the analysis unit <NUM> by wire or wireless transmission so that the analysis unit <NUM> is able to construct the image of the sample under test <NUM> according to the diffraction result.

In this embodiment, the analysis unit <NUM> may use simple image processing method to construct the image of the sample under test <NUM>, for example, comparing the obtained diffraction result with diffraction result data stored in the user's data base to accelerate defect detection. If the obtained diffraction result mismatches the diffraction result data, a further defect classification may be applied to a specific region of the sample under test <NUM>, in order to repair defects in the specific region of the sample under test <NUM>.

Since the EUV pulse laser radiation beam is absorbable to the atmosphere environment. Therefore, in some embodiments, the defect detection apparatuses <NUM> and <NUM> are implemented in the vacuum environment.

It should be understood that this invention is not limited to defect detection for mask, but is also suitable for defect detection for patterned wafer or non-patterned wafer, and further suitable for measurement of dose of photoresist and measurement of optical performance (e.g., transmittance and reflectance) of the mask pellicle.

Claim 1:
An extreme-ultraviolet (EUV) radiation light source generation apparatus (<NUM>, <NUM>, <NUM>, <NUM>), characterized by comprising:
a pump laser (<NUM>), configured to provide a pulse laser radiation beam;
at least one pulse shaping unit (1100A, 1100B, 1100C), wherein each one of the at least one pulse shaping unit (1100A, 1100B, 1100C) is configured to conduct a spectrum extending operation and a phase compensation operation to the pulse laser radiation beam, and the phase compensation operation is configured to make a plurality of frequency components of the pulse laser radiation beam emitted by the pulse shaping unit to be substantially in phase;
a wavelength conversion unit (<NUM>), configured to conduct a center wavelength conversion operation to the pulse laser radiation beam; and
a high-order harmonics generation unit (<NUM>), configured to receive the pulse laser radiation beam processed by the at least one pulse shaping unit (1100A, 1100B, 1100C) and the center wavelength conversion operation, and configured to focus the received pulse laser radiation beam to a high order harmonic generation medium (Gm) to generate a high order harmonic radiation beam (<NUM>).