EUV LITHOGRAPH SYSTEM WITH 3D SCANNING AND TUNING MODULES

Abstract

Method for an extreme ultraviolet lithography system, EUV lithography system (10) comprising a radiation source (14) having a laser device which is equipped with a mechanism for generating EUV radiation (18), comprising: Collecting a laser beam profile (102) of a laser beam (62) from the laser device in a 3-dimensional mode, 3D mode, Collecting an EUV energy distribution of the EUV radiation (18) generated by the laser beam (62) in 3D mode, Performing an analysis of the laser beam profile (102) and the EUV energy distribution, which leads to analysis data, and Adjusting the radiation source (14) according to the analysis data to improve the EUV radiation (18).

Description

BACKGROUND

[0001] This application claims priority over the preliminary US application 63 / 317,142 entitled “SYSTEM AND METHOD FOR LITHOGRAPHY 3D PLASMA DIAGNOSTICS”, which was filed on March 7, 2022 and is incorporated herein in its entirety by cross-reference.

[0002] The integrated semiconductor (IC) industry has experienced exponential growth. Technological advances in IC materials and design have produced generations of ICs, each generation featuring smaller and more complex circuits than the previous one. Function density (i.e., the number of interconnected components per unit area of ​​the chip) has generally increased throughout IC development, while geometric size (i.e., the smallest component (or trace) that can be produced using a manufacturing process) has decreased. This miniaturization process (scaling) offers fundamental advantages by increasing production efficiency and reducing associated costs. However, such miniaturization has also increased the complexity of IC processing and manufacturing.For these advances to be realized, similar developments in IC processing and manufacturing are required. For example, there is a growing need for higher-resolution lithography processes. One such lithographic technique is extreme ultraviolet lithography (EUVL). EUVL employs scanners that utilize light in the extreme ultraviolet (EUV) range, which has a wavelength of approximately 1 nm to 100 nm. EUV scanners tend to use reflective rather than refracting optics, i.e., mirrors instead of lenses. While existing lithographic techniques are generally suitable for their intended purposes, they are not entirely satisfactory in every respect.

[0003] Publication US 2020 / 0393687 A1 discloses an EUV lithography system comprising an EUV light source unit with a laser plasma source. The system also includes a laser monitor that measures the excitation laser profile.

[0004] Publication US 2020 / 0057382 A1 discloses a similar EUV lithography system that has an EUV energy monitor which measures the energy of the generated EUV radiation or its variation.

[0005] From publication US 2021 / 0349396 A1, an EUV lithography system is known which has a measuring arrangement to calculate a 3D distribution of the plasma by Thomson scattering measurements from multiple directions. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Aspects of this disclosure are best understood from the detailed description below, when read together with the accompanying figures. It should be noted that, in accordance with standard industry practice, various features are not drawn to scale. In fact, the dimensions of the various features may have been arbitrarily enlarged or reduced for the sake of clarity. Fig. Figure 1 shows a block diagram of an EUV lithography system with an EUV control system, constructed according to some embodiments. Fig. Figure 2 shows a schematic view of an EUV lithography device system embedded with a 3D guard, constructed according to some embodiments. Fig. Figure 3 is a schematic view of the EUV radiation source in the EUV lithography system of Fig. 1, constructed according to some embodiments. Fig. Figure 4 is a schematic view of the EUV radiation source in the EUV lithography system of Fig. 1, constructed according to some embodiments. Fig. Figure 5 is a schematic view of the target material droplets used to extract plasma and EUV radiation energy from the plasma in the EUV lithography system of Fig. 1 to produce, constructed according to some embodiments. Fig. Figure 6 shows an LLP process (LLP: laser-produced plasma) constructed according to some embodiments. Fig. Figure 7 shows a block diagram of an EUV control system constructed according to some embodiments. Fig. Figure 8 is a schematic view of a correlation analysis implemented by a correlation analysis unit of the EUV control system, constructed according to some embodiments. Fig. Figure 9 is a schematic view of a machine adaptation analysis implemented by a tool adaptation unit of the EUV control system, constructed according to some embodiments. Fig. Figure 10 is a schematic view of a modeling process implemented by a modeling unit of the EUV control system, constructed according to some embodiments. Fig. Figure 11 shows a schematic view of a machine learning process implemented by a machine learning unit of the EUV control system, built according to some embodiments. Fig. Figure 12 is a schematic view of a process for collecting data, analyzing the collected data, extracting the information from the analysis, and controlling the lithography system for improved lithographic processes by the EUV control system, constructed according to some embodiments. Fig. Figure 13 shows a schematic view of a data process that includes collecting data, modeling and analyzing the collected data, set up according to some embodiments. Fig. 14 is a flowchart of a process based on the EUV lithography system of Fig. 1 is applied, constructed according to some embodiments. DETAILED DESCRIPTION

[0007] The following disclosure provides many different embodiments, or examples, for implementing various features. Reference numerals and / or letters may be repeated in the various examples described herein. This repetition is for the sake of simplicity and clarity and does not, in itself, imply any relationship between the various disclosed embodiments and / or configurations. Furthermore, specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting.For example, forming a first element over or on a second element, as described below, may include embodiments in which the first and second elements are in direct contact, and may also include embodiments in which additional elements may be formed between the first and second elements, so that the first and second elements may not be in direct contact. Furthermore, forming an element on another element, connected and / or coupled to it, as described in the present disclosure, may include embodiments in which the elements are in direct contact, and may also include embodiments in which additional elements may be formed between the elements, so that the elements may not be in direct contact.

[0008] Furthermore, the present disclosure may repeat reference numbers and / or letters in the various examples. This repetition is for the sake of simplicity and clarity and does not, in itself, prescribe a relationship between the various embodiments and / or configurations discussed. Moreover, forming one element on another, connected and / or coupled to it, in the disclosure below may include embodiments in which the elements are formed in direct contact, and may also include embodiments in which additional elements may be formed between the elements, so that the elements may not be in direct contact. Furthermore, terms relating to spatial relativity, such as "lower", "upper", "horizontal", "vertical", "above", "below", "below", "top", "bottom", "top", "bottom", "top", "bottom", etc., are used in addition to the above.Similarly, derivatives thereof (e.g., "horizontal," "downward," "upward," etc.) are used for the simplicity of this disclosure of the relationship between one element and another. The terms relating to spatial relativity are intended to cover different orientations of the device comprising the elements. Furthermore, when a number or range of numbers is described by "approximately," "about," and the like, it is intended that the term encompasses numbers that lie within a reasonable range, including the number described, such as within + / - 10% of the number described or other values ​​as understood by a person skilled in the art. For example, the term "approximately 5 nm" encompasses the dimensional range from 4.5 nm to 5.5 nm.

[0009] The present disclosure relates to an extreme ultraviolet lithography device (EUV lithography device) integrated with an EUV control system designed to monitor, analyze, tune, and control the EUV lithography device for improved performance. The present disclosure also includes a method that uses the control system to monitor a laser beam, plasma, contamination, or EUV radiation, collect and analyze 3D diagnostic data (including correlation and machine learning), identify root causes, and actively tune and control parameters of the EUV lithography device, thereby improving the lithography process when the EUV lithography device is used in the fabrication of integrated circuits (ICs).In particular, the method and the EUV control system are related to an EUV lithography device for structuring IC structures in advanced technology nodes. The IC structure can include field-effect transistors (FETs), FinFETs, or multiple-gate devices, such as gate-all-around devices (GAA devices), according to various embodiments.

[0010] Fig. Figure 1 is a block diagram of a lithography system 10, constructed according to some embodiments. The lithography system 10 can also be generally referred to as a scanner capable of performing lithographic exposure processes with a suitable radiation source and exposure mode. In the present embodiment, the lithography system 10 is an extreme ultraviolet (EUV) lithography system designed for exposing a photoresist layer with EUV light. The photoresist layer is a suitable material sensitive to EUV light. The lithography system 10 comprises one or more EUV lithography devices 12 designed for performing an exposure process using EUV radiation.An EUV lithography device 12 comprises an EUV source 14 (or simply referred to as source vessel 14) to generate EUV radiation 18, and an exposure chamber 16 designed to carry out a lithography exposure process using the EUV radiation 18.

[0011] The radiation source 14 has an enclosed space that is maintained in a hydrogen environment for protection and to reduce contamination. The radiation source 14 has various components configured to generate EUV radiation 18. In the disclosed embodiment, the radiation source 14 has: a laser source 20 to provide a laser beam; an LPP module (LPP: laser-generated plasma) 22 to generate plasma using the laser beam; and an EUV module 24 to collect and focus the EUV radiation 18 generated by the plasma. The exposure chamber 16 is maintained in a vacuum environment to reduce unwanted absorption of the EUV radiation 18. According to various embodiments, the exposure chamber 16 may have: a masking table 28 to mount a photomask (or reticule); a wafer stage 30 to mount a semiconductor substrate (such as, for example, a silicon dioxide, a silicon dioxide, or ...a wafer) to attach, and an EUV optic 26 designed to modulate the EUV radiation so that an image of the structure or a section thereof defined on the photomask is directed onto the semiconductor substrate or, in particular, onto a photoresist layer deposited on the semiconductor substrate.

[0012] The lithography system 10 also includes a control system (or EUV control system) 32, which is integrated with the EUV lithography device 12. The control system 32 is designed with mechanisms to monitor various parameters of the EUV lithography device 12, collect 3D diagnostic data from it, analyze the collected 3D data, identify the root causes of any undesired problems, and actively tune and control variables of the EUV lithography device 12, thus improving and expanding the EUV lithography device 12 and the associated process when the EUV lithography device 12 is used in the manufacturing of integrated circuits (ICs).

[0013] The EUV control system 32 comprises various units, modules, and components that are integrated and configured to perform different functions. Different sections of the EUV control system 32 can be distributed across different locations, such as being partially embedded in and configured within the EUV lithography device 12; or partially operating independently or connected to the EUV lithography device 12 via internet communication (such as a wired internet connection, a Wi-Fi connection, a Bluetooth connection, another suitable connection, or a combination thereof).

[0014] The EUV control system 32 comprises various monitors 34 for monitoring and collecting various pieces of information associated with the EUV lithography device 12, or in particular the radiation source 14 of the EUV lithography device 12. In the disclosed embodiment, the EUV control system 32 comprises: a laser monitor 34A, which is equipped and configured with a mechanism for monitoring a laser beam generated by the laser source 20; a plasma monitor 34B, which is equipped and configured with a mechanism for monitoring the plasma generated by the laser beam; and an EUV monitor 34C, which is equipped and configured with a mechanism for monitoring the EUV radiation 18 generated from the plasma.In some embodiments, the EUV control system 32 comprises several sets of the aforementioned monitors (34A, 34B, and 34C), each set being embedded in a corresponding EUV lithography device 12 and connected to other components of the EUV control system 32. The EUV control system 32 may additionally or alternatively include one or more other monitors configured and designed to monitor other parameters, such as target droplet contamination and plasma stability, which are collected and used in the analysis of the radiation source 14.

[0015] In particular, various monitors 34 are designed and configured to collect 3D data associated with the radiation source 14, which is more effective in providing additional and sufficient information for the analysis of the radiation source 14. Accordingly, the monitors 34 are collectively referred to as the 3D Diagnostic Module (3DDM) 34. 3D means that the module 34 is capable of monitoring and collecting data in three or more dimensions, such as two spatial dimensions plus a time dimension, three spatial dimensions, or three spatial dimensions plus a time dimension. When considering the time dimension, the data is collected over a period of time in addition to a spatial variation of the corresponding parameter (such as laser light intensity, plasma intensity, or EUV radiation intensity).The 3DDM 34 provides a way to build a 3D diagnostic model with sufficient and relevant data for improved analysis, such as a correlation analysis between the laser profile, plasma distribution and EUV radiation.

[0016] As mentioned above, the 3DDM 34 features various units for monitoring and collecting different signals associated with the EUV source. In particular, the 3DDM 34 is designed to collect 3D data, which can be achieved using various available or future technologies.

[0017] The laser monitor 34A incorporates any suitable technology sensitive to the laser light from the laser source 20. In some embodiments, the laser monitor 34A incorporates one or more photodiodes sensitive to the laser beam from the laser source 20 and configured to receive the laser beam. In particular, the laser monitor 34A is capable of collecting 3D data of the laser beam. For example, the laser monitor 34A incorporates several photodiodes arranged in an array such that the laser beam from the laser source 20 can be effectively captured and collected. In other embodiments, the laser monitor 34A incorporates other suitable detectors (sensitive to the laser beam from the laser source 20), such as...Photomultipliers, optoisolators, integrated optical circuit elements (IOC elements), photoresistors, photoconductive camera tubes, charge-coupled imaging devices, injection laser diodes, quantum cascade lasers, photoemitting camera tubes or a combination thereof.

[0018] The plasma monitor 34B incorporates any suitable technology sensitive to the plasma generated by the laser beam of the laser source 20 through the LPP module 22. In some embodiments, the plasma monitor 34B incorporates one or more Faraday rings sensitive to the plasma generated by the laser beam (such as plasma density) and configured to effectively monitor the plasma. In particular, the plasma monitor 34B is capable of collecting 3D plasma data, such as a plasma density distribution. For example, the plasma monitor 34B incorporates multiple Faraday rings arranged in an array such that plasma generated by the LPP module 22 can be effectively collected. In other embodiments, the plasma monitor 34B incorporates other suitable detectors (sensitive to plasma density), such as a light scattering detector, an electron multiplier, or a combination thereof.

[0019] The EUV monitor 34C incorporates any suitable technology sensitive to the EUV radiation 18 generated from the plasma. In some embodiments, the EUV monitor 34C includes one or more photodiodes sensitive to and configured to receive the EUV radiation 18. The scanning mechanism of the EUV monitor 34C may be similar to that of the scanning unit of the laser monitor 34A, since both scan photons, albeit photons in different spectral ranges. In some examples, the EUV monitor 34C incorporates multiple photodiodes arranged in an array such that the EUV radiation 18 from the plasma (e.g., reflected, in particular, from the EUV collectors) can be effectively collected. In other embodiments, the EUV guard 34C has other suitable detectors (which are sensitive to EUV radiation 18), such as e.g.Photomultipliers, photoresistors, hybrid pixel detectors, other suitable devices, or a combination thereof.

[0020] With further reference to Fig. The EUV control system 32 further comprises other modules, such as an analysis module 40, a control module 42, and a database 44, which are integrated with the 3DDM 34. The database 44 is coupled to the 3DDM 34 so that the 3D data collected by the 3DDM 34 is sent to and stored in the database 44. The analysis module 40 is coupled to the database 44 so that the analysis module 40 can access 3D data from the 3DDM 34. The analysis module 40 is designed with one or more mechanisms to effectively analyze the 3D data and find the root causes of any problems associated with the radiation source 14. The control module 42 is coupled to the analysis module 40 and is also coupled to the EUV lithography device 12. The control module 42 is designed with one or more suitable mechanisms to control the radiation source 14 of the EUV lithography device 12 according to the result from the analysis module 40.In some examples, the control module 42 tunes the radiation source 14 of the EUV lithography device 12 so that the EUV lithography device 12 is tuned to eliminate or reduce the identified problems, and an EUV exposure process using the EUV lithography device 12 is improved and extended.

[0021] Fig. Figure 2 is a schematic partial view of various modules of the lithography system 10, constructed according to several embodiments. In particular, it shows Fig. 2 the EUV lithography device 12 and the monitoring module 34. In particular, the monitoring module 34 of the EUV control system 32 is embedded in and thus integrated into the EUV lithography device 12.

[0022] The EUV lithography device 12 is further described with reference to Fig. 2 described. In the present embodiment, the EUV lithography device 12 is an EUV lithography tool designed to expose a photoresist layer with EUV radiation. The photoresist layer is a suitable material sensitive to EUV radiation. The lithography device 12 uses a radiation source 14 to generate EUV radiation 18, such as EUV light having a wavelength in the range of approximately 1 nm to 100 nm. In the illustrated embodiment, the radiation source 14 generates EUV light with a wavelength centered at approximately 13.5 nm. To further the embodiment, the center wavelength is at 13.5 nm with a 1% FWHM bandwidth. Accordingly, the radiation source 14 is also referred to as the EUV radiation source 14.In the present embodiment, the EUV radiation source 14 utilizes a laser-generated plasma (LPP) mechanism to generate the EUV radiation 18. In particular, the radiation source 14 comprises a laser source 20, an LPP module 22, and an EUV module 24, as described above in . Fig. 1 described. In particular, the laser source 20 has one or more high-power CO2 laser systems.

[0023] The EUV lithography device 12 also uses a lighting device 50. In various embodiments, the lighting device 50 comprises: various optical refractive components, such as a single lens or a lens system comprising multiple lenses (zone plates), or alternatively, reflective optics (for the EUV lithography system), such as a single mirror or a mirror system comprising multiple mirrors, to direct light from the radiation source 14 onto a masking table 28. In the present embodiment, in which the radiation source 14 generates light in the EUV wavelength range, reflective optics are used.

[0024] The EUV lithography device 12 includes the mask stage 28, which is configured to hold a mask 52. In some embodiments, the mask stage 28 includes an electrostatic clamping device (e-chuck) for holding the mask 52. This is because gas molecules absorb EUV light, and the EUV exposure chamber 16 is maintained in a vacuum environment to prevent EUV intensity loss. In the disclosure, the terms mask, photomask, and reticule are used to refer to the same object. In the present embodiment, the EUV lithography device 12 is an EUV lithography system, and the mask 52 is a reflection mask. An example structure of the mask 52 is provided for illustration. The mask 52 has a substrate made of a suitable material, such as a low thermal expansion material (LTEM) or fused silica.In various examples, the LTEM features TiO2-doped SiO2 or other suitable materials with low thermal expansion. The mask 52 has reflective multilayers (MLs) deposited on the substrate. The ML has several film pairs, such as molybdenum-silicon film pairs (Mo / Si film pairs) (e.g., a layer of molybdenum above or below a layer of silicon in each film pair). Alternatively, the ML can have molybdenum-beryllium film pairs (Mo / Be film pairs), or other suitable materials that can be designed to strongly reflect EUV light. The mask 52 can also have a cover layer, such as ruthenium (Ru), placed on the ML to protect it from oxidation. The mask 52 also has an absorption layer, such as a tantalum nitride (TaBN) layer, deposited over the ML.The absorption layer is structured to define a layer of an integrated circuit (IC). Alternatively, a different reflective layer can be deposited over the ML and structured to define a layer of an integrated circuit, thereby forming an EUV phase-shift mask.

[0025] The EUV lithography device 12 also includes an optical projection module (or optical projection box (POB)) 54 for imaging the structure of the mask 52 onto a semiconductor substrate 56 mounted on a substrate stage 30 of the EUV lithography device 12. In the present embodiment, the POB 54 has reflective optics for projecting the EUV light. The EUV light, which carries the image of the structure defined on the mask 52, is directed by the mask 52 and collected by the POB 54. The illumination device 50 and the POB 54 are collectively referred to as an optical module of the EUV lithography device 12.

[0026] The EUV lithography device 12 also includes the substrate stage (or wafer stage) 30 for mounting the semiconductor substrate 56. In the present embodiment, the semiconductor substrate 56 is a semiconductor wafer, such as a silicon wafer or another type of wafer to be patterned. The semiconductor substrate 56 is coated with the photoresist layer, which is sensitive to the radiation beam, e.g., EUV light in the present embodiment. Various components, including those described above, are integrated together and can be operated to perform EUV lithography exposure processes.

[0027] In some embodiments, the 3DDM 34 or sections thereof is embedded in the EUV lithography device 12 and thus integrated with a configuration and a mechanism for monitoring various parameters of the radiation source 14. In various embodiments, the 3DDM 34 includes a laser monitor 34A, a plasma monitor 34B, an EUV monitor 34C, other suitable monitors, or a combination thereof.

[0028] In various embodiments, the monitoring module 34 includes the laser monitor 34A, which is configured to monitor a laser beam, such as a (spatial) laser beam profile and the laser beam profile variation over time.

[0029] In some embodiments, the monitoring module 34 includes the plasma monitor 34B, which is configured to monitor a plasma, such as a spatial plasma distribution and the fluctuation of the plasma distribution over time.

[0030] In various embodiments, the monitoring module 34 includes the EUV monitor 34C, which is configured to monitor EUV radiation, such as a (spatial) EUV radiation profile and the fluctuation of the EUV radiation profile over time.

[0031] In some embodiments, the plasma monitor 34B is designed with a mechanism to additionally or alternatively monitor the plasma stability. The plasma state of the radiation source 14 varies over time. For example, a target material is used to generate plasma, and the state of the target material changes over time; for instance, the droplet size, the ionization rate of the target material (which will be described below), and the plasma concentration change accordingly. The fluctuation in the plasma state also causes the fluctuation in the EUV intensity in the lithography exposure process. In some examples, a separate monitor, designed to monitor plasma stability, oversees the plasma state.

[0032] In some examples, the monitoring module 34 includes a utilization monitor with a mechanism for monitoring the utilization of the target material droplets within the dose span. The utilization monitor tracks historical target material droplet utilization data for semiconductor wafers previously processed in the EUV lithography device 12. Alternatively, the utilization monitor is integrated into the plasma monitor 34B to monitor various plasma-associated parameters. The dose span and other terms will be described in more detail later.

[0033] In some other embodiments, the function of the plasma monitor 34B can be implemented by the EUV monitor 34C. For example, if the dose error relates to plasma instability, the dose error is extracted from the monitored EUV energy by monitoring the EUV energy with the EUV monitor 34C. The EUV lithography device 12 may also include other modules or be integrated (or coupled) with other modules.

[0034] In some embodiments, the EUV lithography device 12 includes a gas supply module designed to provide hydrogen gas to the radiation source 14, effectively protecting the radiation source 14 (such as the collector) from contamination. In other embodiments, the EUV lithography device 12 includes a magnet configured to guide the plasma through the appropriate magnetic field.

[0035] In particular, radiation source 14 is furthermore in Fig. Figure 3 shows a schematic view, constructed according to some embodiments. The radiation source 14 uses an LPP mechanism (LPP: laser-generated plasma) to generate plasma and further to generate EUV light from the plasma. The radiation source 14 has one or more lasers 20, such as a pulsed carbon dioxide laser (CO2 laser), to generate a laser beam 62. In an illustrative embodiment, the laser source 20 has two laser devices, one for generating a pre-pulse impact on a target material 68 and another for generating a main pulse impact on the target material 68. The laser 20 may further have one or more laser amplifiers to further increase the power of the laser beam. In the disclosed embodiment, two laser devices may each have a laser amplifier or, alternatively, share a laser power.The laser beam 62 is directed through an output window 64, which is integrated with a collector (also referred to as an LPP collector or EUV collector) 66. The output window 64 employs a suitable material that is essentially transparent to the laser beam. The collector 66 is designed with suitable coating materials and shapes that act as a mirror for EUV collection, reflection, and focusing. In some embodiments, the collector 66 is designed to have an ellipsoidal geometry with dual foci, such as a primary focus and an intermediate focus. In some embodiments, the coating material of the collector 66 is similar to the reflective multilayer of the EUV mask 52. In some examples, the coating material of the collector 66 has a multilayer (such as multiple Mo / Si film pairs) and may further include a cover layer (such as...The collector 66 has a layer of silicon nitride (Ru) that is stacked on the ML to substantially reflect the EUV light. In some embodiments, the collector 66 may further have a lattice structure designed to effectively scatter the laser beam directed at the collector 66. For example, a silicon nitride layer is stacked on the collector 66 and structured to have a lattice structure.

[0036] The laser beam 62 is directed to heat a target material 68, thereby generating a high-temperature plasma that further produces EUV radiation (or EUV light) 18. In the present embodiment, the target material 68 is tin (Sn). The target material 68 is supplied in droplets. These target material droplets (such as tin droplets) are also simply referred to as droplets. The EUV radiation 18 is collected by the collector 36. The collector 66 further reflects and focuses the EUV radiation for the lithography exposure processes.

[0037] The radiation source 14 is set up in an enclosed space (referred to as a source vessel). The source vessel is kept in a vacuum environment because air absorbs EUV radiation. In some embodiments, the source vessel is further provided to protect it from hydrogen contamination. In some embodiments, the 2DDM 34 is embedded in the radiation source and is configured to monitor various parameters of the radiation source.

[0038] The radiation source 14 may also have several other components that are integrated together, such as those that are in Fig. 4 are shown. Fig. Figure 4 is a schematic view of a radiation source 14 constructed according to some embodiments. The radiation source 14 utilizes an LPP mechanism. The radiation source 14 comprises a laser 20, such as a pulsed CO2 laser, to generate a laser beam 62. The laser beam 62 is directed by a beam delivery system 72, such as one or more arranged mirrors, onto a focusing lens 74 to focus the laser beam 62. The laser beam 62 is further projected through the output window 64 integrated with the collector 66. The laser beam 62 is focused onto the target material 68 (such as tin droplets 68) in the primary focus of the collector 66, thereby generating high-temperature plasma. The tin droplets 68 are generated by a tin droplet generator 76. A tin collector 78 is further configured to collect the tin droplets.The high-temperature plasma generated in this way also produces EUV radiation 18, which is collected by the collector 66. The collector 66 further reflects and focuses the EUV radiation onto an intermediate focus and is directed for EUV exposure processes.

[0039] The pulses of laser 20 and the droplet generation rate of tin droplet generator 76 are controlled to synchronize them, ensuring that the tin droplets 68 receive constant peak powers from the laser pulses of laser 20. In some examples, the tin droplet generation frequency ranges from 20 kHz to 100 kHz. For instance, laser 20 includes a laser circuit designed to control the generation of the laser pulses. The laser circuit and the tin droplet generator 76 are coupled to synchronize the generation of the laser pulses and the generation of the tin droplets 68.

[0040] In some embodiments, the radiation source 14 further comprises a central obscuring element 79, which is designed and configured to obscure the laser beam 62. The radiation source 14 may also include an intermediate focus obscuring module (IF obscuring module) 80, such as a quick-connect IF obscuring module, which is configured to direct the EUV radiation 18 to the intermediate focus 81 with improved conversion gain. The IF obscuring module 80 may additionally act to obscure the laser beam 62 for improved performance.

[0041] The radiation source 14 can also be integrated with or coupled to other units / modules. For example, a gas supply module is coupled to the radiation source 14, providing hydrogen gas for various protective functions, including effective protection of the collector 66 from contamination by tin particles (tin residues).

[0042] The target material droplets 68 and the EUV radiation 18, and the corresponding mechanism are further described in Fig. Figure 5 illustrates this. The target material droplets 68 are grouped into bursts 82, which are separated by intervening time and intervening droplets 84. In the present embodiments, the intervening droplets 84 are not excited by the laser beam 62 during the EUV exposure process.

[0043] During an EUV exposure process, a series of bursts 82 are provided in the radiation source 14. Each burst 82 contains multiple target material droplets 68 and is configured to provide a specific EUV energy (referred to as the burst target energy or BTE) during the EUV exposure process. When a semiconductor substrate 56 is exposed by the lithography system 10 using the EUV energy, the exposure dose can be achieved if each burst 82 contributes EUV energy to the burst target energy. The target material droplets 68 in each burst are defined into two categories: dose droplets 86 and edge droplets 88. During an EUV exposure process, the dose droplets 86 in each burst 82 are excited by the laser to generate plasma and, accordingly, plasma-generated EUV radiation with an EUV energy that reaches the burst target energy.The marginal droplets 88 in each burst 82 are reserved for dose control and are used to support the dose droplets, maintaining the burst's EUV energy to achieve the target burst energy. These marginal droplets 88 are collectively referred to as the dose margin. Due to plasma intensity instability, not all droplets contribute to the nominal EUV energy. For example, if the laser-generated plasma from a dose droplet has a lower density, the EUV energy collected by that dose droplet will be lower than normal. If the EUV energy generated from the dose droplets 86 in the burst 82 cannot reach the target burst energy, the marginal droplets 88, or a subset thereof, are excited to contribute additional EUV energy, ensuring that the total EUV energy from the burst 82 reaches the target burst energy. The number of target material droplets in each burst is Nt.The number of dose droplets (86) in each burst is designed to be Nd, and the number of edge droplets in each burst is designed to be Nm. There is a relationship between these parameters, namely Nt = Nd + Nm. Therefore, if Nt is given, increasing the dose margin decreases the target burst energy.

[0044] In some embodiments, the laser source 20 can have two or more laser devices configured such that the corresponding laser beams 62 are directed sequentially to a target material droplet (e.g., a tin droplet) 68 as the droplet moves from the droplet generator 76 to the droplet catcher 78. Therefore, the energies from the laser beams of the different laser devices are accumulated to achieve a target value, so that the laser-generated plasma is able to produce the desired EUV radiation. This is further described with reference to Fig. 6 described. Fig. Figure 6 is a schematic view of the droplet 68 interacting with laser beams, and of a process from laser to plasma and further to EUV radiation, which is set up according to some embodiments. The horizontal axis 94 indicates time (not to scale) or the progress of EUV generation over time.

[0045] As in Fig. As shown in Figure 6, the target material droplet 68, such as a tin droplet, is struck in a spherical liquid by a first laser beam (laser pre-pulse or laser PP) and changes its shape along its path, e.g., into a pancake shape. Subsequently, a second laser beam (laser main pulse or laser MP) strikes the target material droplet 68 and transforms it into plasma 91 (such as tin plasma or Sn plasma), which further generates EUV radiation 18. Meanwhile, residues 92 are also generated from the plasma in various forms, such as Sn particles, and are further deposited on the surface of the EUV collector 66, causing contamination that reduces the reflection efficiency of the EUV collector 66, leads to increased equipment downtime of the lithography system 10, and increases manufacturing costs.The energy transformation process described above involves a transition from laser energy to plasma energy, and a transition from plasma energy to EUV energy. The transition between PP and MP is similar to the transition between t1 and t2 in [reference missing]. Fig. 6 indicates that the target material droplet 68 is struck during the laser pre-pulse and its physical state is changed, e.g., its shape is altered and fragmented, and Sn ions are generated. As in a region between t2 and t2 in Fig. As indicated at 6, the target material droplet 68 is struck by the main laser pulse and changes its physical state, such as being vaporized and ionized, leading to a plasma state 91. According to the MP, as in a region between t3 and t4 in Fig. Figure 6 shows that after the main laser pulse, the plasma 91 emits sections with sufficient EUV radiation 18 and accompanying residues 92, which are deposited on the surface of the EUV collector 66. The EUV radiation 18 is directed to the photomask 52 for lithographic processes.

[0046] Fig. Figure 7 is a block diagram of the EUV control system 32, which is constructed according to some embodiments. The 3DDM 34 is in Fig. As described in section 1, the 3DDM 34 includes, for example, the laser monitor 34A, the plasma monitor 34B, the EUV monitor 34C, and other suitable monitors designed to monitor a corresponding signal from the radiation source 14 and collect the data from it. It is not repeated here for the sake of simplicity.

[0047] In some embodiments, the 3DDM 34 may further include a contamination monitor 34D, which is equipped with a mechanism for detecting contamination from the target material, such as tin particles, when the plasma is generated by the laser. These tin particles can be generated when the plasma is generated by the laser beam and can be deposited on the surfaces of the EUV collector 66, causing contamination and a deterioration of the EUV reflectivity of the EUV collector 66. In some embodiments, the contamination monitor 34D includes one or more photodiodes that are sensitive to the laser beam from the laser source 20 and configured to receive the laser beam. In particular, the laser monitor 34A is capable of collecting 3D data of the laser beam.For example, the laser monitor 34A includes several photodiodes arranged in an array such that the laser beam from the laser source 20 can be effectively captured and collected. In other embodiments, the laser monitor 34A includes other suitable detectors (sensitive to the laser beam from the laser source 20), such as photomultipliers, optoisolators, integrated optical circuit elements (IOC elements), photoresistors, photoconductive camera tubes, charge-coupled imaging devices, injection laser diodes, quantum cascade lasers, photoemitting camera tubes, or a combination thereof.

[0048] The plasma monitor 34B incorporates any suitable technology sensitive to the plasma generated by the laser beam of the laser source 20 through the LPP module 22. In some embodiments, the plasma monitor 34B incorporates one or more Faraday rings sensitive to the plasma generated by the laser beam (such as plasma density) and configured to effectively monitor the plasma. In particular, the plasma monitor 34B is capable of collecting 3D plasma data, such as a plasma density distribution. For example, the plasma monitor 34B incorporates multiple Faraday rings arranged in an array such that plasma generated by the LPP module 22 can be effectively collected. In other embodiments, the plasma monitor 34B incorporates other suitable detectors (sensitive to plasma density), such as a light scattering detector, an electron multiplier, or a combination thereof.

[0049] The EUV monitor 34C incorporates any suitable technology sensitive to the EUV radiation 18 generated from the plasma. In some embodiments, the EUV monitor 34C includes one or more photodiodes sensitive to and configured to receive the EUV radiation 18. The scanning mechanism of the EUV monitor 34C may be similar to that of the scanning unit of the laser monitor 34A, since both scan photons, albeit photons in different spectral ranges. In some examples, the EUV monitor 34C incorporates multiple photodiodes arranged in an array such that the EUV radiation 18 from the plasma (e.g., reflected, in particular, from the EUV collectors) can be effectively collected. In other embodiments, the EUV monitor 34C has other suitable detectors (which are sensitive to EUV radiation 18), such as e.g.Photomultipliers, photoresistors, hybrid pixel detectors, other suitable devices, or a combination thereof.

[0050] The EUV control system 32 further comprises an analysis module 40, a control module 42, and a database 44. Various parameters of the radiation source 14 are monitored and collected by the 3DDM 34, stored in the database 44, analyzed by the analysis module 40, and fed back to the control module 42 to control the radiation source 14 for the improved lithography system 10 and improved lithographic processes implemented by the lithography system 10.

[0051] Database 44 has a physical structure, such as a storage device with an input and an output for inward and outward data transmission. Examples of the storage device include a non-volatile storage device (NVM device), such as a flash memory device or ferroelectric random-access memory (RAM), a volatile memory, such as a static RAM device (SRAM device), another suitable storage device, or a combination thereof. Database 44 has different sections for storing respective data, such as a database unit 44A for laser profile data, a database unit 44B for target contamination data, a database unit 44C for plasma distribution data, a database unit 44D for EUV radiation data, and a database unit 44E for analysis data.The database 44 may also include other suitable data units for various data associated with the radiation source 14 or even the EUV lithography device 12.

[0052] The analysis module 40 has various correlation analysis units 40A that analyze the correlations between different parameters, such as a correlation between the laser beam profile and the plasma distribution, a correlation between the plasma distribution and the EUV radiation energy, a correlation between the laser beam profile and the target material residues, a correlation between the laser beam profile and the target material residues, a correlation between the laser beam profile and the EUV energy, and other correlations.

[0053] An example of correlation is in Fig. 8 is shown and is described in detail below. Fig. 8(a) is a laser beam profile expressed in terms of the intensity (I) of the laser beam (I) relative to the XY surface. The XY surface is defined as a surface in Fig. 3. The laser beam is directed along a Z-direction from the laser source 20 to the target material 68, while the X and Y directions are two perpendicular directions defined in a Cartesian coordinate system. The XY surface is defined as a flat surface that intersects the Z-axis at the position of the target material droplets 68. The corresponding profile of the laser beam is also defined in Fig. Figure 8(b) is shown in a schematic view. Two axes represent X and Y, while the other axis represents the intensity (I) of the laser beam. The corresponding distribution or profile of the laser beam is further shown in Fig. Figure 8(c) is shown in a schematic view. One axis represents X, while the other axis represents the intensity (I) of the laser beam. Two example profiles, 96 and 98, are shown in Fig. Figure 8(c) illustrates the first laser beam profile 96, which exhibits a Gaussian distribution, and the second laser beam profile 96, which exhibits a non-uniform distribution that differs from the Gaussian distribution. In the disclosed embodiment, the first laser beam profile 96 results in a better generated plasma 91 and less residue, and furthermore in higher EUV radiation 18 with greater conversion efficiency (CE); and the second laser beam profile 98 results in a poorly generated plasma 91 and more residue, and furthermore in degraded EUV radiation 18 with lower CE. In this example, the laser beam profile is correlated with the plasma profile, the residue, and the EUV radiation energy. Such a correlation provides information and an indication of how to tune (e.g., a laser beam profile) for improved EUV radiation and less residue.

[0054] The analysis module 40 also features various tool adaptation units 40B that collect and analyze various parameters, such as the laser beam profile, plasma distribution, EUV radiation energy, and residue amount of various lithography systems, so that useful information is extracted which is fed back to tune and control a lithography system for improved EUV radiation and less residue.

[0055] An example is in Fig. Figure 9 is shown and described in detail below. Data are collected from various lithographic tools and compared with regard to the laser beam and plasma distribution. Fig. Figure 9 shows the laser beam profile for various lithography systems, such as tools A to E. Specifically, the laser beam profile for each tool is compiled from three different phases: the pre-pulse laser beam at the target material 68; the main pulse laser beam after the laser amplifier; and the main pulse laser beam at the target material 68. Various beam profiles from the respective lithography systems and phases are shown in Fig. Figure 9 illustrates this. Each of these can differ from the others, such as a circular, eccentric, peanut-shaped, or asymmetric profile, and so on. It should be noted that these are for illustrative purposes only. Corresponding plasma distributions are also collected by these lithography systems. EUV radiation energy and CE can also be collected by these lithography systems. These data are then analyzed to find a relationship between the laser beam profile and the plasma distribution, or even a relationship between the plasma distribution and the EUV radiation. In particular, the relationship between the laser beam profile and the plasma distribution is further assigned to each of the aforementioned laser beam profiles.

[0056] In some embodiments, the above analysis yields the following results. Each lithography system exhibits a specific laser beam profile, leading to different plasma thermodynamics and a nonlinear effect during laser plasma generation. Regions of higher laser intensity provide greater EUV radiation and a greater CE. Regions of lower laser intensity cause insufficient heating and an insufficient plasma generation effect, resulting in more residue of the target material (such as tin). Further analysis involves comparing the similarity of laser beams between different lithography systems and establishing a correlation between the laser beam profile and the EUV radiation energy.These results can further be used in a feedback loop to control and tune the laser source, including laser realignment, laser beam focusing and timing control to synchronize the target material droplet 68 and the laser source pulse.

[0057] The analysis module 40 also features various modeling units 40C that generate corresponding models (such as a laser beam model, a plasma model, an EUV radiation model, or a target material contamination model) from the collected data for further analysis (such as correlation analysis). For example, the correlation analysis can comprise two stages. In the first stage, the raw data collected by the 3DDM 34 is first processed to filter out irrelevant data or noise, generating preprocessed data also referred to as a model of the laser beam, plasma, or EUV radiation. In the second stage, the preprocessed data is sent to the correlation units 40A for a correlation analysis that includes correlations between the laser beam profile, the plasma distribution, the EUV radiation energy, and the target material residues.

[0058] An example is in Fig. 10 is shown and is described in detail below. Fig. In Figure 10(a), the laser beam profile is expressed in a Cartesian coordinate system around the focused target material droplet. Reference symbol 102 represents the laser beam profile, while reference symbol 104 represents an effective area. The effective area 104 specifies the area in which the plasma generated by the laser beam 62 in that area can effectively and efficiently generate EUV radiation 18 and maintain sufficient EUV energy during generation, which is, for example, greater than a predefined criterion. In one example, this criterion is that the EUV radiation intensity is 5 mJ / m². 3 is. This is further in Fig. 10(b) is shown. In the disclosed modeling method, only the effective area 104 is important and will be analyzed further. To promote embodiments, the space in which the EUV energy is distributed is further subdivided into three-dimensional grids (3D grids), such as a cubic grid in a Cartesian coordinate system in 3D. These grids are evaluated individually using the criterion to determine the effective area. Other areas are removed and discarded, as shown in Fig. Figure 10(c) shows the geometric center of the effective area 104, which is marked with the reference symbol 106. Fig. Figure 10(d) provides further examples of the laser beam profile 102 and the corresponding effective area 104. In this case, the target material droplet laser beam should be positioned in the center 106 of the effective area 104 for improved EUV radiation generation. This can be used to control and tune the laser beam 62 and synchronize the target material droplet 68. Fig. 10 is further described below in conjunction with other units of the analysis module 40.

[0059] The analysis module 40 also includes one or more machine learning units 40D that analyze various collected or preprocessed data using one or more machine learning technologies, such as an artificial neural network. In some embodiments, this data is fed into the machine learning unit 40D as training data, using the enhanced EUV radiation energy as the desired output. This allows the machine learning unit 40D to identify the optimized conditions for generating the increased EUV radiation energy and reduced residue contamination. These conditions can be fed back into the control module 42 to adjust and fine-tune the corresponding lithography system to the optimized conditions for improved lithography processes.

[0060] One embodiment of the machine learning process by machine learning unit 40D is further described with reference to Fig. 10. In this embodiment, the predefined EUV energy criterion is used as the desired output, the laser beam profile and the corresponding EUV radiation energy are used as training data, and the machine learning unit 40D could identify the desired position of the target material droplet 68. In an illustrative example, the desired position of the target material droplet 68 is at the position (X=0.34 µm, Y=4.5 µm, and X=-112 µm), which can be supplied to the control module 42 for setting.

[0061] The machine learning process by Unit 40D of Machine Learning is further described with reference to Fig. 11 described. Fig. Figure 11 contains a table with four examples in four columns. The second row of the table lists laser beam profiles, the first row lists the effective ranges of the laser beams, and the third row lists the machine learning results. For each example, the effective ranges obtained through the machine learning process are provided, which are similar to the effective ranges obtained through the modeling method described above. The similarities between the two methods are provided in the fourth row. The results indicated that the similarities are significant and both methods are effective.

[0062] Fig. Figure 12 shows a process for collecting data, analyzing the collected data, extracting information from the analysis, and controlling the lithography system for improved lithographic processes by using various modules of the EUV control system 32. In some examples, the data is collected by the guards 34, and the collected data includes targeting data (the target material position relative to the laser beam's focal point) and 3DDM data of the laser beam profile, plasma distribution, and EUV radiation energy. The analysis is implemented by the analysis module 40 and can include modeling, correlation analysis, tool adaptation, machine learning, or a combination thereof. In one example, the analysis generates the correlation between the EUV radiation energy and the targeting position. The correlation results are further fed back into the control module 42 to control the laser source 20 (such as...).to adjust the laser beam alignment and focus) and the timing of the target material droplet 68 so that the targeting position is aligned with the position of increased or maximized EUV radiation energy. In particular, the effective area 104 is associated with higher vaporization, higher ion energy, and higher EUV radiation energy, and lower residue accumulation, while the other area is associated with lower vaporization, lower ion energy, and lower EUV radiation energy, and greater residue accumulation. The analysis also includes comparing the similarity between the laser beam profile and the effective area; comparing a 3D acquisition rate between the beam profile and the effective data area; and building a time-resolved effective model to compare the targeting map.

[0063] Fig. Figure 13 shows a different data process that includes collecting data, modeling, and analyzing the collected data. Fig. 13(a) The plasma distribution 91 is collected in 3D mode. Then a statistical criterion, such as 3σ, is used to filter out scattering data, resulting in the preprocessed distribution (or preprocessed plasma distribution) 112, as shown in Fig. Figure 13(b) shows the standard deviation of the normal distribution. The parameter σ represents the standard deviation of the normal distribution. Then, the data space 114 is extracted from the preprocessed distribution 112, as shown in Figure 13(b). Fig. Figure 13(c) illustrates this. The data space 114 defines the outer outline of the preprocessed distribution. The effective area 116 is determined within the data space 114 using a suitable analysis, such as correlation analysis, machine learning, another suitable method, or a combination thereof, as shown in Fig. Figures 13(d) and (e) illustrate this. In an illustrative example, the effective region is the plasma region in which sufficient EUV radiation energy is generated. Furthermore, effective space 116 is extracted from effective region 114, as shown in Fig. Figure 13(f) illustrates this. The effective space 116 provides information for controlling and tuning the lithography system 10 for improved lithographic processes. For example, the geometric center of the effective space 116 is fed back into the control module 42 to set the laser beam 62 orientation and the target material droplet timing 68 for improved EUV radiation.

[0064] With renewed reference to Fig. In section 7, the control module 42 is further described according to various embodiments. In some embodiments, the control module 42 comprises a laser alignment unit 42A, a target determination position control unit 42B, a laser pulse delay adjustment unit 42C, and a vessel control unit 42D. The laser alignment unit 42 has a mechanism for adjusting the orientation of the laser beam so that the laser beam profile is appropriately tuned. The mechanism of the laser alignment unit 42A comprises: a stepper motor, a piezoelectric material, another suitable mechanism, or a combination thereof for adjusting the orientation of the laser beam; and optical components for focusing the laser beam so that the laser beam profile is optimized for increased EUV radiation.

[0065] The target positioning control unit 42B has a mechanism to adjust the delivery of the target material droplet 68 so that the laser beam is focused on the correct position of the target material droplet 68. The mechanism of the target positioning control unit 42B has a circuit for fine-tuning the delivery time.

[0066] The laser pulse delay adjustment unit 42C has a mechanism for adjusting the timing of the laser pulse so that the laser pulse (prepulse or main pulse) is generated at the correct time, thus synchronizing the laser pulse with the delivery of the target material droplet 68. This ensures that the prepulse laser beam or the main pulse laser beam can strike the correct position of the target material droplet 68. The mechanism of the laser pulse delay adjustment unit 42C includes a circuit for fine-tuning the laser device to generate a laser pulse at the correct time.

[0067] The vessel control unit 42D has one or more mechanisms to adjust various parameters of the radiation source 14, such as vessel pressure, vessel gas flow rate, and vessel temperature, so that the laser beam 62, the plasma 91, and the EUV radiation 18 are optimized according to feedback from the data analysis. These parameters are important for contamination and EUV radiation. For example, the vessel temperature is a parameter for controlling the vaporization of the target material, and therefore it affects contamination and EUV radiation energy. In another example, the vessel hydrogen flow rate and pressure are parameters for controlling the contamination of the target material and EUV radiation energy. The mechanism of the vessel control unit 42D includes a flow control device to adjust the flow rate of the vessel gas, such as...to adjust the hydrogen flow rate, a circuit to fine-tune the delivery time; a pressure sensor and flow control device to adjust the vessel gas flow rate so that the vessel pressure is optimized; and a heat sensor and circuit to control the heating device power so that the vessel temperature is optimized for improved EUV radiation.

[0068] Fig. Figure 14 shows a flowchart of the process 120 for an EUV lithography process implemented by the lithography system 10, constructed according to some embodiments.

[0069] Method 120 comprises a process 122 in which an EUV photomask 52 is loaded into the lithography system 10, which is then operational to perform an EUV lithography exposure process. The photomask 52 has an IC structure that is to be transferred onto a semiconductor substrate, such as a semiconductor wafer 56. Process 122 may further include various steps, such as mounting the photomask 52 on the masking table 28 and performing an alignment.

[0070] Method 120 comprises a process 124 in which the wafer 56 is loaded into the lithography system 10. The wafer 56 is coated with a photoresist layer. In the present embodiment, the photoresist layer is sensitive to the EUV radiation 18 from the radiation source 14 of the lithography system 10.

[0071] Method 120 comprises a process 126 in which the lithography system 102 is controlled, in particular the radiation source 14 is adjusted for improved EUV radiation. Process 126 further comprises several steps (or sub-processes) to adjust and fine-tune the lithography system 10 for improved lithography processes. In the disclosed embodiment, process 126 comprises a step 136 to collect data from the radiation source 14 by the monitoring module 34, a step 138 to analyze the collected data by the analysis module 40, and a step 140 to adjust the radiation source 14 by the control module 42 according to the analysis results obtained in step 138.

[0072] In particular, in some embodiments, the collection of data from the radiation source 14 by the monitoring module 34 includes the collection of data on the laser beam profile by the laser monitor 34A; the collection of data on the plasma distribution by the plasma monitor 34B; the collection of data on the EUV radiation energy by the EUV monitor 34C; the collection of data on sulfur contamination by the sulfur contamination monitor 34D; or a combination thereof. In some embodiments, the analysis of the collected data by the analysis module 40 includes the analysis of the collected data by the correlation analysis unit 40A; the analysis of the collected data by the tool adaptation unit 40B; the analysis of the collected data by the modeling unit 40C; the analysis of the collected data by the machine learning unit 40D; or a combination thereof.The setting of the radiation source 14 by the control module 42 includes: setting the laser beam profile by the laser alignment unit 42A; setting the delivery of the target material droplet by the target positioning control unit 42B; setting the synchronization of the laser pulse (pre-pulse or main pulse) by the laser pulse delay setting unit 42C; setting the vessel pressure, vessel gas flow rate and / or vessel temperature by the vessel control unit 42D; or a combination thereof.

[0073] Method 120 comprises a process 128 in which a lithography exposure process is carried out on the wafer 56 in the lithography system 10. In process 128, the laser 20 and the tin droplet generator 68 are synchronized by means of a suitable mechanism, such as a control circuit with a timer for controlling and synchronizing both (in particular, laser pulses and tin droplet generation are synchronized). The synchronized laser 20 excites the target material droplets 68 and generates a plasma, thereby generating EUV radiation. During process 128, the generated EUV radiation is directed onto the photomask 52 (by the illumination device 50) and further projected onto the photoresist layer deposited on the wafer 56 (by the POB 54), thereby forming a latent image on the photoresist layer. In the present embodiment, the lithography exposure process is implemented in a scanning mode.

[0074] In particular, during the lithography exposure process, the target material droplets 68 are excited by the laser beam 62 to generate a plasma 91 and furthermore to generate the EUV radiation 18. Various steps in the 126 can be implemented simultaneously or overlapping with the lithography exposure process. For example, the collection of data by the monitors 34 during process 136 and the analysis of the collected data by the analysis module 40 during process 138.

[0075] Procedure 120 may include other operations to complete the lithographic structuring process. For example, Procedure 120 may include an operation 130 in which the exposed photoresist layer is developed to form a photoresist structure that has several defined openings within it. In one example, the photoresist layer has a positive tone; the exposed portion of the photoresist layer is removed by the developing solution. In another example, the photoresist layer has a negative tone; the exposed portion of the photoresist layer remains; and the unexposed portions are removed by the developing solution.

[0076] In particular, after the lithographic exposure process in step 128, the wafer 56 is transferred from the lithographic system 10 to a developing unit to perform step 130. Step 120 may also include further steps, such as various baking steps. For example, step 120 may include a post-exposure baking step (PEB step) between steps 128 and 130.

[0077] Method 120 can further include additional operations, such as operation 132, to perform a manufacturing process on the wafer 56 through the openings of the photoresist structure. In one example, the manufacturing process involves applying an etching process to the semiconductor substrate 56 or depositing a layer of material thereon using the photoresist structure as an etching mask. In another example, the manufacturing process involves performing an ion implantation process on the semiconductor substrate 56 using the photoresist structure as an implantation mask. After operation 132, the photoresist layer can be removed by wet stripping or plasma ashing.

[0078] The present disclosure provides an EUV lithography system with 3D scanning and tuning modules. The EUV lithography system comprises a 3D diagnostic module embedded in the radiation source vessel and analysis and control modules for tuning the radiation source according to the analysis of the 3D data of the radiation source. By implementing the disclosed EUV lithography system 10 and the method applied thereto, the EUV lithography system 10 is fine-tuned to increase the EUV radiation energy, reduce residue contamination, and improve the lithography exposure process. The disclosed EUV lithography system 10 comprises an EUV lithography tool integrated with an EUV control system 32, which further includes a monitor 34, an analysis module 40, a control module 42, and a database 44. The guardian 34 of the EUV control system 32 is embedded in the radiation source 14 of the EUV lithography device 12.In some examples, the procedure includes collecting data from radiation source 14 by the monitor 34, analyzing the collected data by the analysis module 40, and adjusting radiation source 14 by the control module 42 according to the analysis.

[0079] In one exemplary aspect, the present disclosure provides a method for an extreme ultraviolet lithography system (EUV lithography system) comprising a radiation source that includes a laser device equipped with a mechanism for generating EUV radiation. The method comprises collecting a laser beam profile of a laser beam from the laser device in a 3-dimensional mode (3D mode); collecting an EUV energy distribution of the EUV radiation generated by the laser beam in 3D mode; performing an analysis of the laser beam profile and the EUV energy distribution, resulting in analysis data; and adjusting the radiation source according to the analysis data to improve the EUV radiation.

[0080] In another exemplary aspect, the present disclosure provides an extreme ultraviolet lithography system (EUV lithography system). The EUV system comprises: a radiation source for generating EUV radiation, wherein the radiation source includes a laser source, a target material droplet generator, and an EUV collector, arranged in a vessel; a mask stage configured for mounting an EUV mask; a wafer stage configured for mounting a semiconductor wafer; an optical module for directing the EUV radiation from the radiation source to image an IC structure defined on the EUV mask onto the semiconductor wafer in a lithography exposure process; and an EUV control system integrated with the radiation source.The EUV control system comprises: a 3D diagnostic module (3DDM) designed to collect data from the radiation source in 3D mode, an analysis module designed to analyze the collected data, and an EUV control module designed to tune the radiation source. The 3DDM is embedded within the radiation source. The analysis module is coupled to the 3DDM and the EUV control module. The EUV control module is coupled to the analysis module and the radiation source.

[0081] In a further example aspect, the present disclosure provides a method for an extreme ultraviolet lithography system (EUV lithography system) comprising a radiation source that includes a laser device and a laser-generated plasma mechanism for generating EUV radiation. The method includes: collecting three-dimensional data (3D data) of the radiation source, wherein the 3D data exhibit a laser beam profile and the EUV energy of the EUV radiation; performing an analysis of the laser beam profile and the EUV energy, resulting in correlation data; and adjusting the radiation source according to the correlation data to enhance the EUV radiation.

[0082] The foregoing outlines features of several embodiments so that a person skilled in the art can better understand the aspects of the present disclosure. A person skilled in the art should recognize that he or she can readily use the present disclosure as a basis for designing or modifying other processes and structures to perform the same tasks and / or achieve the same advantages of the embodiments presented herein.

Claims

[1] Method for an extreme ultraviolet lithography system, EUV lithography system (10) comprising a radiation source (14) having a laser device which is equipped with a mechanism for generating EUV radiation (18), comprising: Collecting a laser beam profile (102) of a laser beam (62) from the laser device in a 3-dimensional mode, 3D mode, Collecting an EUV energy distribution of the EUV radiation (18) generated by the laser beam (62) in 3D mode, Performing an analysis of the laser beam profile (102) and the EUV energy distribution, which leads to analysis data, and Adjusting the radiation source (14) according to the analysis data to improve the EUV radiation (18). [2] The method of claim 1, further comprising carrying out an EUV lithography exposure process on a semiconductor substrate (56) using the EUV lithography system (10) with the adjusted radiation source. [3] The method of claim 2, further comprising: After performing the EUV lithography exposure process, a development process is carried out on the semiconductor substrate (56), whereby a structured photoresist layer is formed on the semiconductor substrate (56), and Performing a manufacturing process on the semiconductor substrate (56) through openings in the structured photoresist layer. [4] Method according to claim 3, wherein the manufacturing process comprises an etching process and an ion implantation process. [5] Method according to any one of the preceding claims, wherein the EUV lithography system (10) comprises an EUV lithography device (12) which further comprises the radiation source (14), the EUV lithography system (10) comprises an EUV control system (32) which is integrated with the EUV lithography device (12), and the EUV control system (32) comprises a monitoring module (34), an analysis module (40), and a control module (42), wherein the monitoring module (34) is embedded in the radiation source (14). [6] Method according to claim 5, wherein the monitoring module (34) includes a laser monitor (34A), a plasma monitor (34B), and an EUV monitor (34C), the analysis module (40) includes a correlation analysis unit (40A), a modeling unit (40C) and a machine learning unit (40D), and the control module (42) comprises a laser alignment unit (42A), a target positioning control unit (42B), a laser pulse delay setting unit (42C) and an EUV source vessel control unit (42D). [7] Method according to claim 6, wherein the collection of a laser beam profile (102) of a laser beam (62) from the laser device in a 3-dimensional mode (3D mode) includes the collection of the laser beam profile (102) of the laser beam (62) by the laser monitor (34A), the collection of an EUV energy distribution of the EUV radiation (18) generated by the laser beam (62) in 3D mode includes, a collection of the EUV energy distribution of the EUV radiation (18) by the EUV guardian (34C), and Performing an analysis of the laser beam profile (102) and the EUV energy distribution includes performing the analysis of the laser beam profile (102) and the EUV energy distribution by the analysis module (40). [8] Method according to claim 6 or 7, wherein adjusting the radiation source (14) according to the analysis data to improve the EUV radiation (18) comprises adjusting the laser beam profile (102) according to the analysis data by the laser alignment unit (42A). [9] Method according to any one of the preceding claims 6 to 8, wherein adjusting the radiation source (14) according to the analysis data to improve the EUV radiation (18) comprises adjusting a delivery of a target material droplet (68) according to the analysis data by the target determination position control unit (42B). [10] Method according to any one of the preceding claims 6 to 9, wherein adjusting the radiation source (14) according to the analysis data to improve the EUV radiation (18) comprises adjusting the generation of a laser pulse from the laser device according to the analysis data by the laser pulse delay adjustment unit (42C). [11] Method according to any one of the preceding claims 6 to 10, wherein adjusting the radiation source (14) according to the analysis data to improve the EUV radiation (18) comprises adjusting an EUV source vessel parameter by the EUV source vessel control unit (42D), and wherein the EUV source vessel parameter comprises one of an EUV source vessel pressure, an EUV source vessel gas flow rate, and an EUV source vessel temperature. [12] Extreme ultraviolet lithography system, EUV lithography system (10), comprising: a radiation source (14) to generate EUV radiation (18), wherein the radiation source (14) comprises a laser source (20), a target material droplet generator and an EUV collector (66) arranged in an EUV source vessel, a mask table (28) designed to hold an EUV mask (52), a wafer platform (30) designed for mounting a semiconductor wafer (56), an optical module designed to direct the EUV radiation (18) from the radiation source (14) to image an IC structure defined on the EUV mask (52) onto the semiconductor wafer (56) in a lithography exposure process, and an EUV control system (32) integrated with the radiation source (14), the EUV control system (32) comprising: a 3-dimensional diagnostic module, 3DDM (34) designed to collect data from the radiation source (14) in 3D mode, an analysis module (40) designed to analyze the collected data, and an EUV control module designed to adjust the radiation source (14), wherein the 3DDM (34) is embedded in the radiation source (14), wherein the analysis module (40) is coupled to the 3DDM (34) and the EUV control module, and wherein the EUV control module is coupled to the analysis module (40) and the radiation source (14). [13] EUV lithography system (10) according to claim 12, wherein the 3DDM (34) comprises: a laser monitor (34A) for monitoring a laser beam (62) from the laser source (20), a plasma monitor (34B) for monitoring a plasma generated by the laser beam (62), and an EUV monitor (34C) for monitoring the EUV radiation generated from the plasma (18). [14] EUV lithography system (10) according to claim 13, wherein the 3DDM (34) further comprises a contamination monitor (34D) for monitoring contamination by target material droplets (68) supplied by the target material droplet generator. [15] EUV lithography system (10) according to claim 13 or 14, wherein the analysis module (40) comprises: a correlation analysis unit (40A) to analyze a correlation between a laser beam profile (102) of the laser beam (62) and an EUV radiation energy of the EUV radiation (18), a modeling unit (40C) for extracting impact data from the collected data, and a machine learning unit (40D) to extract an effective laser beam profile according to associated EUV radiation (18) [16] EUV lithography system (10) according to any one of the preceding claims 13 to 15, wherein the control module (42) comprises: a laser alignment unit (42A) with a mechanism for adjusting the laser beam profile (102) of the laser beam (62) according to an analysis result from the analysis module (40), a target determination position control unit (42B) with a mechanism for adjusting a delivery of a target material droplet (68) supplied by the target material droplet generator, a laser pulse delay adjustment unit (42C) with a mechanism for controlling the generation of a laser pulse from the laser device to synchronize the laser pulse and the target material droplet (68), and an EUV source vessel control unit (42D) with mechanisms for setting at least one of an EUV source vessel pressure, an EUV source vessel flow rate, and an EUV source vessel temperature of the EUV source vessel. [17] Method for an extreme ultraviolet lithography system, EUV lithography system (10) comprising a radiation source (14) comprising a laser device and an LPP mechanism (LPP: laser-generated plasma) for generating EUV radiation (18), comprising: Collecting 3-dimensional data (3D data) of the radiation source (14), wherein the 3D data includes a laser beam profile (102) and an EUV energy of the EUV radiation (18), Performing an analysis of the laser beam profile (102) and the EUV energy, leading to correlation data, and Adjusting the radiation source (14) according to the correlation data to improve the EUV radiation (18). [18] The method of claim 17, further comprising: Performing an EUV lithography exposure process on a semiconductor substrate (56) using the EUV lithography system (10) with the adjusted radiation source, After performing the EUV lithography exposure process, a development process is carried out on the semiconductor substrate (56), whereby a structured photoresist layer is formed on the semiconductor substrate (56), and Performing a manufacturing process on the semiconductor substrate (56) through openings in the structured photoresist layer. [19] Method according to claim 17 or 18, wherein the EUV lithography system (10) comprises an EUV lithography device (12) which further comprises the radiation source (14), the EUV lithography system (10) comprises an EUV control system (32) which is integrated with the EUV lithography device (12), and the EUV control system (32) comprises a monitoring module (34), an analysis module (40), and a control module (42), wherein the monitoring module (34) is embedded in the radiation source (14). [20] Method according to any one of the preceding claims 17 to 19, wherein the monitoring module (34) includes a laser monitor (34A), a plasma monitor (34B), and an EUV monitor (34C), the analysis module (40) includes a correlation analysis unit (40A), a modeling unit (40C) and a machine learning unit (40D), the control module (42) comprises a laser alignment unit (42A), a target positioning control unit (42B), a laser pulse delay adjustment unit (42C) and an EUV source vessel control unit (42D), The collection of 3-dimensional data (3D data) includes the collection of laser beam profile data (102) by the laser monitor (34A) and EUV energy data of the EUV radiation (18) by the EUV monitor (34C), Performing an analysis of the laser beam profile (102) and the EUV energy includes identifying a correlation between the laser beam profile (102) and the EUV energy of the EUV radiation (18), and The adjustment of the radiation source (14) according to the correlation data includes the adjustment of the laser beam profile (102) by the laser alignment unit (42A).

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