Patent Publication Number: US-11662668-B2

Title: Lithography contamination control

Description:
BACKGROUND 
     To produce semiconductor devices, a semiconductor substrate, such as a silicon wafer, which is a raw material for the semiconductor devices, must go through a sequence of complicated and precise process steps. Often, to complete the sequence, the wafer must be physically transported from one piece of fabrication equipment to another piece of fabrication equipment. Within these pieces of fabrication equipment, various processes such as diffusion, ion implantation, chemical vapor deposition, photolithography, etching, physical vapor deposition, and chemical mechanical polishing are carried out on the semiconductor substrate. 
     Photolithography, also called optical lithography or lithography, is a process used to transfer a sophisticated pattern of a photomask (e.g., mask) onto a photoresist coated surface of the substrate (e.g., wafer) using light. Subsequent processing includes etching that creates a permanent pattern of the photomask on the substrate. 
     In the modern photolithography process, a light source that generates extreme ultraviolet (EUV) light is used for transferring the highly sophisticated pattern onto the substrate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. 
         FIG.  1    is a schematic view of an extreme ultraviolet light lithography system configured with a contamination abatement module according to one or more embodiments of the present disclosure, which is configured to reduce the amount of contaminants that enter into a scanner of the extreme ultraviolet light lithography system. 
         FIG.  2    is a schematic cross-sectional view of the extreme ultraviolet light source connected to a scanner of the extreme ultraviolet light lithography system according to one or more embodiments of the present disclosure. 
         FIG.  3    is a schematic view of a hollow connection member (configured with an inlet of an exhaust pump) which provides a passage of an extreme ultraviolet light generated from the extreme ultraviolet light source to the scanner according to one or more embodiments of the present disclosure. 
         FIG.  4    is a cross-sectional view of the hollow connection member configured with an inlet that includes a plurality of suction openings according to one or more embodiments of the present disclosure. 
         FIG.  5    is a schematic view of a hollow connection member configured with the inlet of the exhaust pump and a magnet member according to one or more embodiments of the present disclosure. 
         FIG.  6    is a cross-sectional view of the hollow connection member illustrated in  FIG.  5    according to one or more embodiments of the present disclosure. 
         FIG.  7    is a schematic partial view of an extreme ultraviolet light lithography system with the hollow connection member configured with an inlet in the circular configuration according to one or more embodiments of the present disclosure. 
         FIG.  8    is a front view of the inlet in the circular configuration illustrated in  FIG.  7    according to one or more embodiments of the present disclosure. 
         FIG.  9    is a partial side view of the inlet in the circular configuration illustrated in  FIG.  7    according to one or more embodiments of the present disclosure. 
         FIG.  10    is a flow chart illustrating a method of a lithography process implemented by the extreme ultraviolet light lithography system including the hollow connection member configured with the inlet according to one or more embodiments of the present disclosure. 
         FIG.  11    is a flow chart illustrating a method of a lithography process implemented by the extreme ultraviolet light lithography system configured with the inlet in the circular formation according to one or more embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. 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, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. 
     Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly. 
     An extreme ultraviolet light lithography system or tool includes a light source and a scanner for an exposure step in a semiconductor fabrication process. The light source generates extreme ultraviolet light and includes a condenser lens and mirror (e.g., collector) to reflect and focus the generated extreme ultraviolet light into the intermediate focus point. The focused extreme ultraviolet light is provided to the scanner for the exposure step. The scanner of the extreme ultraviolet light lithography system includes an illuminator, a photomask stage (e.g., reticle stage), which is configured to hold a photomask (e.g., mask), projection optics, and a substrate table (e.g., wafer stage). The extreme ultraviolet light travels from the light source portion of the extreme ultraviolet light lithography system to the scanner portion of the extreme ultraviolet light lithography system via a hollow connection member. 
     Intense extreme ultraviolet light (EUV light) from the light source travels through the condenser lens, the illuminator, the photomask stage, and the projection lens. In the exposure step, the light from the light source is directed onto a photoresist coated substrate (e.g., wafer) on the substrate table, after passing the condenser lens, the illuminator, the photomask stage, and the projection optics. By exposing the substrate to the intense light, a sophisticated pattern from the photomask (mask) is transferred onto the substrate. 
     To generate the intense light (e.g., EUV light) that is suitable for transferring the sophisticated pattern of the photomask (e.g., template or mask for &lt;5 nm fabrication process) onto the photoresist coated surface of the substrate (e.g., wafer) consistently, a high energy light (e.g., carbon dioxide laser and excimer laser) is illuminated to a very small droplet (e.g., a droplet having a 30 μm diameter) that includes tin (Sn) in the source vessel of the light source. Since tin is an efficient generator of the EUV light, the high energy light illuminated to the droplet made of tin causes tin (Sn) excitation. In some embodiments, the droplet includes pure tin (Sn), tin compounds (e.g., SnBr 4 , SnBr 2 , and SnH 4 ), tin-alloys (e.g., tin-gallium alloys, tin-indium alloys, and tin-indium-gallium alloys), or combinations thereof. 
     The tin excitation generates an extremely hot plasma which produces a significant amount of the high intensity EUV light (e.g., light having a center wavelength at about 13.5 nm). In order to use the EUV light in the subsequent exposure step, the EUV light is collected by a collector (e.g., a curved reflective surface with a multi-layer coating) that is configured to reflect the EUV light from the plasma selectively into the intermediate focus point. 
     To maximize or increase the amount of the EUV light reflected and focused into the intermediate focus point, it is beneficial to have the reflective surface of the collector clean from the contaminants, such as tin droplet debris (or fragments) produced during the tin droplet excitation process. To clean or remove the tin debris deposited on the curved reflective surface (hereinafter “collector surface”), a flow of hydrogen gas (H 2 ) is introduced into the source vessel of the light source to etch the tin droplet debris deposited on the collector surface. As a result of a chemical reaction between the hydrogen gas (H 2 ) and the tin (Sn) droplet debris deposited on the collector surface, the hydrogen gas (H 2 ) and the tin (Sn) droplet debris are converted into a volatile tin compound, tin hydride (SnH 4 ). By introducing suitable purge gas (e.g., hydrogen gas and nitrogen gas) into the source vessel, the tin hydride (SnH 4 ) can be removed from the source vessel via a purge outlet. 
     To minimize or decrease the likelihood of the contaminants (e.g., tin debris) produced during the tin excitation process traveling to and depositing on the collector surface, a wafer in the process, and other components of the extreme ultraviolet light lithography system (e.g., illuminator, photomask stage, photomask, reticle, projection optics, and substrate stage), the flow of hydrogen gas (H 2 ) is introduced into the source vessel of the light source that keeps the tin debris flowing away (e.g., circulating) from the inner sidewall of the source vessel of the light source and the collector surface. Additionally, the flow of hydrogen gas (hereinafter “air curtain” or “gas curtain”) reduces the likelihood of the contaminants (e.g., tin debris) flowing into the scanner of the extreme ultraviolet light lithography system by deterring or blocking the flow of the tin debris. 
     As discussed above, the hydrogen gas (H 2 ) that is introduced into the lithography system keeps the collector surface in the light source and components in the scanner less contaminated with the tin debris. Particularly, the flow of hydrogen gas (H 2 ) is arranged to block or deter the flow of the tin debris into the scanner. However, the more hydrogen gas (H 2 ) introduced into the lithography system (e.g., light source) to deter the flow of the tin debris into the scanner, the more likely the hydrogen gas will reduce the intensity of the EUV light generated by the light source. A reduction in intensity of the EUV light can adversely impact the performance of the EUV lithography system. 
     Embodiments in accordance with subject matter described herein include a smart contamination abatement module that is configured to remove the contaminants (particularly, tin debris produced during the tin excitation process) flowing into the scanner and/or is configured to alter the flowing direction of the tin debris before contaminating the various components located in the scanner of the extreme ultraviolet light lithography system (e.g., an illuminator, a photomask stage, photomask, reticle, projection optics, and a substrate table). As discussed above, by circulating the hydrogen gas (H 2 ) within the source vessel, the tin debris, created during the tin excitation process, continuously flows within the source vessel without being deposited on the inner surface of the source vessel. Eventually, most of the tin debris circulated by the air curtain is collected and removed from the source vessel. However, a small portion of tin debris, created during the tin excitation process, which has a high velocity, is not controllable or manageable with the air curtain. The tin debris that is not controllable with the air curtain due to the high velocity may flow into the scanner portion of the extreme ultraviolet light lithography system. Since the scanner is operated under a high vacuum (due to less hydrogen gas in the scanner), the uncontrollable tin debris can be easily sucked into the scanner and contaminate various components in the scanner once the debris passes through the air curtain in the light source. In accordance with various embodiments of the present disclosure, by reducing the amount of contaminants such as the tin debris entering into the scanner, a process yield from the extreme ultraviolet light lithography system is maintained or improved. 
     The contamination abatement module according to one or more embodiments disclosed in the present disclosure is also able to extend the cleaning interval (e.g., preventive maintenance interval) of various components in the scanner. That will reduce significant “tool down time” for the preventive maintenance, which will improve production rates. 
     The contamination abatement module according to one or more embodiments disclosed in the present disclosure is also able to improve or to maintain the intensity of the extreme ultraviolet light provided to the scanner portion of the extreme ultraviolet light lithography system by reducing or minimizing the use of the air curtain (i.e., hydrogen gas (H 2 ) flow). Maintaining the intensity of the extreme ultraviolet light will maintain the quality of the patterns formed in the photoresist on the wafer be processed. 
       FIG.  1    is a schematic view of an extreme ultraviolet light lithography system  100  configured with a contamination abatement module  160  according to one or more embodiments of the present disclosure, which is configured to reduce contaminants entering into a scanner  300  of the extreme ultraviolet light lithography system  100 . As noted above, such contaminants may be caused by the tin excitation process that occurs at a light source  200  according to one or more embodiments of the present disclosure. 
     Referring to  FIG.  1   , the extreme ultraviolet light lithography system  100  includes the light source  200  configured to generate extreme ultraviolet (EUV) light and a scanner  300  that is operable to perform a lithography exposing processes using the EUV light from the light source  200 . In the present embodiment, the scanner  300  of the extreme ultraviolet light lithography system  100  exposes a photoresist layer (e.g., coated layer) on a substrate  350  (e.g., semiconductor wafer) to the EUV light. The photoresist layer is a material sensitive to the EUV light. Extreme ultraviolet light lithography system  100  employs the light source  200  to generate the EUV light (with a wavelength ranging between about 1 nm and about 100 nm). In one particular example, the light source  200  generates the EUV light with a wavelength centered at about 13.5 nm. In the present embodiment, the light source  200  utilizes a mechanism of laser-produced plasma (LPP) to generate the EUV light, which will be further described later. 
     Extreme ultraviolet light lithography system  100  employs an illuminator  310 . In some embodiments, the illuminator  310  includes various refractive optic components, such as a single lens or a lens system having multiple lenses (zone plates). In some embodiments, the illuminator  310  includes alternatively reflective optics, such as a single mirror or a mirror system having multiple mirrors in order to direct the EUV light from the light source  200  onto a photomask stage  320 , particularly to a mask  330  secured on the photomask stage  320  as illustrated in  FIG.  1   . 
     As discussed above, the extreme ultraviolet light lithography system  100  includes the photomask stage  320  configured to secure the mask  330 . In some embodiments, the photomask stage  320  includes an electrostatic chuck (e-chuck) to secure the mask  330 . Due to the ability of gas molecules, e.g., hydrogen gas molecules or ions, to absorb EUV light, a lithography system for the EUV lithography patterning is maintained in a vacuum environment to avoid the EUV intensity loss. In the current description, the terms of mask and photomask are used to refer to the same item. Often mask is associated with a reticle in the photomask stage  320 . In the present embodiment, the mask  330  is a reflective mask. One exemplary structure of the mask  330  is provided for illustration. Mask  330  includes a substrate with a suitable material, such as a low thermal expansion material (LTEM) or fused quartz. In various examples, the LTEM includes TiO2 doped SiO2, or other suitable materials with low thermal expansion. Mask  330  includes multiple reflective multiple layers (ML) deposited on the substrate. The ML includes a plurality of film pairs, such as molybdenum-silicon (Mo/Si) film pairs (e.g., a layer of molybdenum above or below a layer of silicon in each film pair). Alternatively, the ML may include molybdenum-beryllium (Mo/Be) film pairs, or other suitable materials that are configurable to highly reflect the EUV light. Mask  330  may further include a capping layer, such as ruthenium (Ru), disposed on the ML for protection. Mask  330  further includes an absorption layer, such as a tantalum boron nitride (TaBN) layer, deposited over the ML. The absorption layer is patterned to define a layer of an integrated circuit (IC). Alternatively, another reflective layer may be deposited over the ML and is patterned to define a layer of an integrated circuit, thereby forming an EUV phase shift mask. 
     Extreme ultraviolet light lithography system  100  also includes projection optics  340  for imaging the pattern of the mask  330  onto a substrate  350  (e.g., semiconductor wafer) secured on a substrate table  360  of the extreme ultraviolet light lithography system  100 . In some embodiments, the projection optics  340  have refractive optics. In some embodiments, the projection optics  340  include alternatively reflective optics as illustrated in  FIG.  1   . The light directed from the mask  330 , carrying the image of the pattern defined on the mask  330 , is collected by the projection optics  340 . Illuminator  310  and the projection optics  340  are collectively referred to an optical module of the extreme ultraviolet light lithography system  100 . 
     Extreme ultraviolet light lithography system  100  includes the substrate table  360  to secure the substrate  350 . In the present embodiment, the substrate  350  is a semiconductor wafer, such as a silicon wafer or other type of wafer to be patterned (e.g., SiC). Substrate  350  is coated with the photoresist layer sensitive to the radiation beam, such as EUV light, in the present embodiment. Various components including those described above are integrated together and are operable to perform lithography exposing processes. 
     Extreme ultraviolet light lithography system  100  may further include other modules or be integrated with (or be coupled with) other modules. In various embodiments, the extreme ultraviolet light lithography system  100  includes a gas supply module  150  designed to provide the hydrogen gas (H 2 ) to the light source  200  for the purposes discussed above (e.g., cleaning and circulating the tin debris for removal). In various embodiments, the extreme ultraviolet light lithography system  100  includes the contamination abatement module  160 . In some embodiments, the contamination abatement module  160  includes an exhaust pump  170  (e.g., vacuum pump) designed to remove air or gas (including hydrogen gas) and contaminants (e.g., tin debris) from the extreme ultraviolet light lithography system  100  (e.g., the light source  200 , the scanner  300 , and a hollow connection member ( 232  in  FIG.  2   ) which will be described later in the disclosure). Exhaust pump  170  can be a pump that is suitable to remove gas molecules (e.g., hydrogen gas) from the extreme ultraviolet light lithography system  100 . In some embodiments, the exhaust pump  170  includes a roughing pump. In some embodiments, the exhaust pump  170  includes a turbomolecular high vacuum pump. In some embodiments, the exhaust pump  170  includes an entrapment pump (e.g., cryopump). In some embodiments, the exhaust pump  170  includes a combination of different types of pumps such as the roughing pump and the turbomolecular high vacuum pump. In some embodiments, the contamination abatement module  160  includes a magnet member  182  (shown as A-H in  FIGS.  5  and  6   ) and a magnet member driver  180  which will be described later in the disclosure. 
       FIG.  2    is a schematic cross-sectional view of the extreme ultraviolet light source  200  connected to the scanner  300  of the extreme ultraviolet light lithography system  100  according to one or more embodiments of the present disclosure. 
     Referring to  FIG.  2   , the extreme ultraviolet light lithography system  100  includes the light source  200  and the scanner  300  (shown in  FIG.  1    and partially shown in  FIG.  2   ), and a hollow connection member  232  between the light source  200  and the scanner  300 . Hollow connection member  232  provides a passage for the EUV light generated at the light source  200  so the EUV light can be provided to the scanner  300 . In other words, via the hollow connection member  232 , the light source  200  supplies the EUV light to the scanner  300  for the exposure step. In the present embodiment, the hollow connection member  232  includes a structure of the light source  200  (adjacent to an intermediate focus point  208 ) that is being used to couple to the scanner  300  and a structure of the scanner  300  (adjacent to the intermediate focus point  208 ) that is being used to couple to the light source  200 . Light source  200  includes a droplet generator  202  for generating droplets (e.g., tin (Sn) droplets) into a source vessel  210 , a droplet catcher  204  for collecting unused or unirradiated droplets from the droplet generator  202 , a collector  206  shaped to reflect the EUV light generated from tin (Sn) excitation selectively into the intermediate focus point  208 , a light generator  220  (e.g., carbon dioxide pulse laser generator and excimer laser generator) for generating pre-pulse light and main pulse light, an aperture  222  (e.g., opening) on the collector  206  that allows the pre-pulse light and the main pulse light to illuminate the droplets in the source vessel  210 , hydrogen gas (H 2 ) outlets  238  (connected to the gas supply module  150 ) for generating the gas curtain within the source vessel  210 , and a controller  400  for controlling the gas supply module  150 , the contamination abatement module  160 , and various other components of the light source  200  including the droplet generator  202 , the droplet catcher  204 , and the light generator  220 . Controller  400  controls these modules and components to minimize or reduce the likelihood of the contaminants (e.g., tin debris) entering into the scanner  300  via the hollow connection member  232 . As will be described later in this disclosure, the exhaust pump  170  and the magnet member driver  180  in the contamination abatement module  160  are configured to reduce the contaminants from entering into the scanner  300  where they may adversely impact the lithography process. 
     In accordance with one or more embodiments of the present disclosure, the controller  400  includes an input circuitry  402 , a memory  404 , a processor  406 , and an output circuitry  408 . Controller  400  includes the (computer) processor  406  configured to perform the various functions and operations described herein including receiving input data from various data sources (e.g., vacuum pressure data from the scanner  300 ) via the input circuitry  402  and transmitting output data (e.g., contamination abatement module control signal for the contamination abatement module  160 ) via the output circuitry  408 . Memory  404  stores the vacuum pressure data received via the input circuitry  402 . Memory  404  may be or include any computer-readable storage medium, including, for example, read-only memory (ROM), random access memory (RAM), flash memory, hard disk drive, optical storage device, magnetic storage device, electrically erasable programmable read-only memory (EEPROM), organic storage media, or the like. 
     In accordance with various embodiments, the light generator  220  (e.g., carbon dioxide pulse laser generator and excimer laser generator) generates a train of light pulses including pre-pulse light and main pulse light, and the light generated by the light generator  220  illuminates the tin droplet traveling in the source vessel  210 . The illumination of the tin droplets creates the tin excitation which generates the plasma that emits the EUV light. To increase or maximize the amount of the plasma generated from the tin excitation with the main pulse light, the pre-pulse light illuminates the tin droplet before the tin droplet is illuminated with the main pulse light. The tin droplet irradiated with the pre-pulse light expands its diameter. When the diameter of the expanded tin droplet (hereinafter “pancake”) matches with the beam size of the main pulse light and the pancake is substantially overlapped with the beam of the main pulse light in the source vessel  210 , there is a higher chance of producing more plasma from the tin excitation with the main pulse light. During the tin excitation process, the contaminants such as tin debris or fragments are generated. 
       FIG.  3    is a schematic view of a hollow connection member  232  (configured with an inlet  500  which is in fluid communication with the exhaust pump  170 ) which provides a passage for an extreme ultraviolet light generated from the extreme ultraviolet light source  200  to the scanner  300  according to one or more embodiments of the present disclosure.  FIG.  4    is a cross-sectional view (A-A′ in  FIG.  3   ) of the hollow connection member  232  configured with the inlet  500  that includes a plurality of suction openings  510  according to one or more embodiments of the present disclosure. 
     Referring to  FIG.  3    and  FIG.  4   , the hollow connection member  232  includes the inlet  500  which includes a plurality of suction openings  510  (e.g., inlet openings through which gas within the hollow connection member  232  can pass) and a gas channel  520  for receiving gas that passes through the suction openings  510 . The gas channel  520  collects the gas that has passed through the suction openings  510 . In the embodiment of  FIGS.  3  and  4   , the suction openings  510  and the gas channel  520  are integrated into the hollow connection member  232 . As illustrated in the exploded portion of  FIG.  4   , the gas channel  520  forms a plenum on an outer surface  533  of the hollow connection member  232 . In the embodiment illustrated in  FIG.  4   , the gas channel  520  is between an inner wall  530  of the hollow connection member  232  and an outer wall  540  of the hollow connection member  232 . Inner wall  530  includes an inner surface  531  and the outer surface  533 . Outer wall  540  includes an outer surface  541  and an inner surface  543 . In some embodiments, the one or more suction openings  510  of the inlet  500  pass through the inner wall  530 . In the embodiment of  FIG.  4   , the outer wall  540  includes a coupling member  560  that connects the gas channel  520  to a gas line  174 . Gas line  174  is coupled to the exhaust pump  170  as illustrated in  FIG.  4   . 
     Exhaust pump  170  is configured to flow gas to or remove gas from the hollow space in the hollow connection member  232 . In some embodiments, the exhaust pump  170  is configured to flow gas to or remove gas from the hollow space in the hollow connection member  232  via the gas line  174 , the coupling member  560 , the gas channel  520 , and the suction openings  510  of the inlet  500  as illustrated in  FIG.  3    and  FIG.  4   . Exhaust pump  170  removes gas from the hollow space in the hollow connection member  232  by producing a pressure differential between exhaust pump  170  and the hollow space. As illustrated in  FIG.  3    and  FIG.  4   , the inlet  500  includes the plurality of suction openings  510  (e.g., inlet openings) arranged within the hollow connection member  232 . In the embodiment illustrated in  FIG.  3    and  FIG.  4   , the suction openings  510 , which are in fluid communication with the exhaust pump  170 , are arranged through the inner wall  530  of the hollow connection member  232  between the intermediate focus point  208  and a first side  234  of the hollow connection member  232  that is adjacent to the scanner  300 . In this example, the flowing pattern of the gas in the hollow connection member  232  can be changed by drawing gas from within the hollow space of the connection member  232  into the gas channel  520  at a location between the intermediate focus point  208  and the first side  234  of hollow connection member  232 . When the gas is drawn from within the hollow space, some of the contaminants (e.g., tin debris) passing through the hollow space of the hollow connection member  232  are influenced by the gas flow pattern (e.g., fluid dynamics) created at the suction openings  510  and are diverted to an inner surface of the walls of the chamber of the scanner  300  rather than towards surfaces of components in the scanner  300  (e.g., the illuminator, the photomask stage, the projection optics, and the substrate table). Some of the contaminants can also be removed from the extreme ultraviolet light lithography system  100  via the suction openings  510 . 
     In some embodiments, the suction openings  510  of the inlet  500  are arranged through the inner wall  530  of the hollow connection member  232  between the intermediate focus point  208  and a second side  236  of the hollow connection member  232  that is adjacent to the light source  200 . In other embodiments, the suction openings  510  of the inlet  500  are arranged through the inner wall  530  of the hollow connection member  232  surrounding the intermediate focus point  208 . In other words, the suction openings  510  can be arranged through the inner wall  530  of the hollow connection member  232  between the first side  234  of the hollow connection member  232  and the intermediate focus point  208 , between the second side  236  of the hollow connection member  232  and the intermediate focus point  208  or through the inner wall  530  of the hollow connection member  232  around the intermediate focus point  208 . 
     In various embodiments of the present disclosure, the vacuum pressure data of the scanner  300  is collected (e.g., measured and recorded) and transmitted to the controller  400  by the vacuum pressure gauge  302  located at the scanner  300 , and the vacuum pressure data of the hollow space of the hollow connection member  232  is collected and transmitted to the controller  400  by the vacuum pressure gauge  304  located at the hollow connection member  232 . In accordance with the vacuum pressure data from the vacuum pressure gauges  302  and  304 , the controller  400  determines the operation speed of the exhaust pump  170  that provides a desired gas volume flow rate at the inlet  500  and adjusts the operation speed of the exhaust pump  170  to provide the desired gas volume flow rate. Controller  400  adjusts the operation speed of the exhaust pump  170  by transmitting a contamination abatement module control signal (e.g., exhaust pump control signal) to the exhaust pump controller  172  of the contamination abatement module  160 . In some embodiments, the contamination abatement module control signal causes the exhaust pump to operate at a speed that causes the hollow space of the hollow connection member  232  to be maintained under a higher vacuum condition (e.g., higher negative pressure) than the vacuum condition of the scanner  300 . In other embodiments, the exhaust pump is operated at a speed that causes the hollow space of the hollow connection member  232  to be maintained under a lower pressure (but not necessarily a vacuum pressure) than the pressure within the scanner  300 . 
     In various embodiments, the controller  400  is configured to generate the contamination abatement module control signal (e.g., exhaust pump control signal) based on the vacuum pressure data of the scanner  300  and the pressure data of the hollow space of the hollow connection member  232  to keep the hollow space under the higher vacuum condition (e.g., higher negative pressure or less air or hydrogen gas) than the vacuum condition of the scanner  300 . In some embodiments, the controller  400  transmits the contamination abatement module control signal (e.g., exhaust pump control signal) based on the vacuum pressure data of the scanner  300  and the hollow space to maintain the hollow space under the higher vacuum condition than the vacuum condition in the scanner  300  by a predetermined pressure difference (e.g., 2 Pa). In some embodiments, the controller  400  is configured to vary the predetermined pressure difference (e.g., setting the predetermined pressure difference from the 2 Pa to 1 Pa and back to 2 Pa) to create variation in the gas flow pattern in the hollow space. The random variation (and/or the periodic variation) in the flow pattern provides variation in the flow pattern that increases the likelihood of diverting the contaminants to the inner surface of the walls of the chamber of the scanner  300  rather than towards surfaces of the components in the scanner  300  (e.g., the illuminator, the photomask stage, the projection optics, and the substrate table). 
     Referring to  FIG.  4   , in some embodiments of the present disclosure, the hollow connection member  232  is configured with the inlet  500  that includes a plurality of suction openings  510  with different sizes to create the variation in the gas flow pattern in the hollow space. As shown in  FIG.  4   , the inlet  500  includes the suction openings  510  with different sizes and/or shapes. The variation with the different shapes and/or sizes (e.g., different diameters, different cross-sectional areas and different opening (nozzle) directions) provides variation in the gas flow pattern that increases the likelihood of diverting the contaminants to the inner surface of the walls of the chamber of the scanner  300  rather than towards surfaces of the components in the scanner  300  (e.g., the illuminator, the photomask stage, the projection optics, and the substrate table). Embodiments in accordance with the present disclosure are not limited to an inlet  500  that includes suction opening  510  with different sizes and/or shapes. In some embodiments, the inlet  500  includes suction openings  510  of the same size and/or the same shape. 
       FIG.  5    is a schematic view of another embodiment of the hollow connection member  232  configured with the inlet  500  and a magnet member  182  (shown as individual magnets A-H in  FIGS.  5  and  6   ) according to one or more embodiments of the present disclosure.  FIG.  6    is a cross-sectional view (AA-AA′ in  FIG.  5   ) of the hollow connection member  232  illustrated in  FIG.  5    according to one or more embodiments of the present disclosure. 
     Referring to  FIG.  5    and  FIG.  6   , the inlet  500 , including the suction openings  510  (e.g., inlet openings in fluid communication with the exhaust pump  170 ) and the gas channel  520  in fluid communication with the suction openings  510  and the exhaust pump  170 , is integrated with the hollow connection member  232 . The hollow connection member  232  illustrated in  FIGS.  5  and  6    is similar to the hollow connection member  232  of  FIG.  4   . The description of hollow connection member  232  presented in the context of  FIG.  4    is equally applicable to the hollow connection member  232  illustrated in  FIGS.  5  and  6   . In addition, the description of the exhaust pump  170 , gas line  174 , coupling member  560 , gas channel  520 , outer wall  540 , inner wall  530 , inner surface  531 , outer surface  533 , inner surface  541  and outer surface  543  above with reference to  FIGS.  3  and  4    is applicable to the features in  FIGS.  5  and  6    identified by the same reference numbers. Accordingly, the description of these features need not be reproduced. 
     In the embodiment illustrated in  FIGS.  5  and  6   , the hollow connection member  232  includes magnet member  182  (shown as individual magnets A-H in  FIGS.  5  and  6   ). A function of magnet member  182  is to create a magnetic field to attract the contaminants (e.g., tin debris) into the suction openings  510  or into the vicinity of suction openings  510  where the gas flow can transport the contaminants out of the hollow connection member  232 . Some of the contaminants that are attracted to or influenced by the magnetic field but are not removed from the hollow connection number  232  and thus remain in the extreme ultraviolet light lithography system  100  (e.g., the hollow connection member  232  and scanner  300 ) are at least diverted toward the inner surface of the walls of the chamber of the scanner  300  rather than traveling toward surfaces of the components in the scanner  300  (e.g., the illuminator, the photomask stage, the projection optics, and the substrate table). As illustrated in  FIG.  5    and  FIG.  6   , in some embodiments, to increase the likelihood of having more tin debris or other contaminants pass through suction openings  510 , each of the suction openings  510  has a cone shaped opening, that is larger (e.g., wider) at inner surface  531  of inner wall  530  and smaller (e.g., narrower) at outer surface  533  of inner wall  530 . As illustrated in  FIG.  6   , in some embodiments, each of the suction openings  510  has a first opening  512  at inner surface  531  of inner wall  530  of the hollow connection member  232  and a second opening  514  at outer surface  533  of inner wall  530 . As shown in  FIG.  6   , a diameter of the first opening  512  is greater than a diameter of the second opening  514 . As illustrated in  FIG.  5    and  FIG.  6   , in some embodiments, the magnet member  182  is located at a respective space between adjacent suction openings  510 . In some embodiments, the magnet member  182  is disposed between the intermediate focus point  208  and the first side  234  of the hollow connection member  232  that is adjacent to the scanner  300 . In some embodiments, the magnet member  182  is disposed between the intermediate focus point  208  and the second side  236  of the hollow connection member  232  that is adjacent to the light source  200 . In some embodiments, the magnet member  182  surrounds the intermediate focus point  208 . Magnet member  182  can be a permanent magnet, an electromagnet, or a permanent magnet and an electromagnet. The strength of magnet member  182  is chosen such that the magnetic field generated by magnet member  182  is sufficient to deflect contaminants that are passing through the magnetic field of magnetic member  182 . 
     In various embodiments of  FIGS.  5  and  6   , the controller  400  is configured to transmit a contamination abatement module control signal (e.g., electromagnet control signal) to the magnet member driver  180  to create variation in the magnetic field in the hollow space of the hollow connection member  232 . The variation in the magnetic field increases the likelihood of diverting the contaminants to the inner surface of the walls of the chamber of the scanner  300  rather than allowing the contaminants to travel in the direction of components in the scanner  300  (e.g., the illuminator, the photomask stage, the projection optics, and the substrate table). For example, the controller  400  is configured to generate an electromagnet control signal to alternately turn on (e.g., apply current to) a first group of electromagnets (A, B, C, D) of the magnet member  182  on an upper portion of the hollow connection member  232  and a second group of electromagnets (E, F, G, H) of the magnet member  182  on a lower portion of the hollow connection member  232 . By doing so, the variation in the magnetic field increases the likelihood of diverting the contaminants to the inner surface of a wall of the chamber of the scanner  300  rather than allowing the contaminants to travel towards and contact components in the scanner  300  (e.g., the illuminator, the photomask stage, the projection optics, and the substrate table). Embodiments in accordance with the present disclosure are not limited to applying current to only a first group comprising electromagnets (A, B, C, D) and a second group of electromagnets (E, F, G, H). In other words, embodiments in accordance with the present disclosure include applying current to combinations of electromagnets other than the first group and the second group described above. For example, current could be applied to every other electromagnet or groupings of electromagnets that include less than four electromagnets. 
     In some embodiments, the controller  400  is configured to transmit the electromagnet control signal to the magnet member driver  180  which causes the magnet member driver  180  to apply different current to different electromagnets to create variation in the magnetic field in the hollow space of the hollow connection member  232 . In other embodiments, the controller  400  is configured to transmit electromagnet control signals to the magnet member driver  180  which cause the magnet member driver  180  to apply current to some or all of the electromagnets for a predetermined period of time, remove current to some or all of the electromagnets for a predetermined trade of time and then repeat the cycle. 
     In some embodiments of the present disclosure, the magnet member  182  includes a plurality of permanent magnets with different magnetic powers to create variation in the magnetic field in the hollow space of the hollow connection member  232 . 
       FIG.  7    is a schematic partial view of an extreme ultraviolet light lithography system  100  with the hollow connection member  232  configured with an alternative embodiment of inlet  500  in  FIGS.  3 - 6   . In  FIG.  7    an inlet  600  includes a circular configuration according to one or more embodiments of the present disclosure.  FIG.  8    is a front view of the inlet  600  having the circular configuration illustrated in  FIG.  7    according to one or more embodiments of the present disclosure.  FIG.  9    is a partial side view of the inlet  600  having the circular configuration illustrated in  FIG.  7    according to one or more embodiments of the present disclosure. Features of the hollow connection member  232  illustrated in  FIGS.  7 - 9    that are the same as features of hollow connection member  232  illustrated in  FIGS.  3 - 6    are identified by the same reference numeral. 
     Referring to  FIGS.  7 - 9   , the inlet  600  includes a plurality of suction arms  610  (e.g., inlet openings in fluid communication with gas line  174  and exhaust pump  170 ) extending from a circular gas channel member  620 . Circular gas channel member  620  is an annular member including an outer wall  640  and an inner wall  630 . Sandwiched between the outer wall  640  and the inner wall  630  is a void or plenum  623 . Plenum  623  is a chamber that is in fluid communication with the plurality of suction arms  610 . Circular gas channel member  620  also includes a coupling member  660  coupling the circular gas channel member  620  to the gas line  174 . Plenum  623  is in fluid communication with exhaust pump  170  via gas line  174  and coupling member  660 . In the embodiment illustrated in  FIG.  9   , the circular gas channel member  620  is received in the first end  234  of hollow connection member  232 . 
     In the embodiment illustrated in  FIG.  7   , the inlet  600  is disposed adjacent to the hollow connection member  232  and in the scanner  300  portion of the extreme ultraviolet light lithography system  100 . In some embodiments, the plurality of suction arms  610  is arranged on the inner wall  630  and pass through an opening in the circular gas channel member  620 . In this manner, the plurality of suction arms  610  are in fluid communication with the circular gas channel member  620 . In some embodiments, the plurality of suction arms  610  are oriented such that their longitudinal axis  900  and  902 , respectively, are at an angle that is parallel to the light pattern (L and L′) of the EUV from the light source  200 . 
     As illustrated in  FIGS.  7 - 9   , in some embodiments, each of the plurality of suction arms  610  is in fluid communication with the exhaust pump  170  via the gas line  174 , the coupling member  660 , and the circular gas channel member  620  (i.e., the hollow space in the circular portion of the inlet  600 . Exhaust pump  170  is configured to flow gas or remove gas (e.g., hydrogen gas) from within hollow connection member  232  through suction arms  610  and, at the same time, remove contaminants (e.g., tin debris) from within hollow connection member  232 . In addition, by flowing gas or removing gas through suction arms  610 , the flow pattern of the gas adjacent to the portion of the hollow connection member  232  adjacent to the scanner  300  is changed. By changing the flow pattern of the gas, some of the contaminants passing the area adjacent to the portion of the hollow connection member  232  adjacent to the scanner  300  are influenced by the changed flow pattern created by the suction from the suction arms  610  and are diverted (e.g., guided) toward the inner surface of an inner wall of a chamber of the scanner  300  rather continuing toward components in the scanner  300  (e.g., the illuminator, the photomask stage, the projection optics, and the substrate table) where the contaminants may accumulate upon impact. 
     In various embodiments of the example of  FIGS.  7 - 9   , the controller  400  is configured to generate contamination abatement module control signals (e.g., exhaust pump control signals) that vary the operation speed of the exhaust pump  170  which has the effect of varying the gas volume flow rate at the suction arms  610  of the inlet  600 . This variation in volume flow rate at the suction arms  610  creates variation in the gas flow patterns that increases the likelihood that contaminants in the portion of the scanner  300  adjacent the hollow connection member  232  are diverted towards an inner surface of an inner wall of the chamber of the scanner  300  rather than continuing toward components in the scanner  300  (e.g., the illuminator, the photomask stage, the projection optics, and the substrate table). 
     In some embodiments, the controller  400  transmits the exhaust pump control signal to the exhaust pump controller  172  based on the vacuum pressure data collected from the scanner  300 . In some embodiments, these exhaust pump control signals cause the exhaust pump  170  to operate under conditions that maintain the scanner  300  at a predetermined pressure while the operation speed of the exhaust pump  170  varies to create the variation in the gas flow patterns at the inlet  600 . 
     As illustrated in  FIG.  9   , each of the suction arms  610  is configured to capture contaminants traveling from the light source  200  without interfering with transmission of the EUV light from the light source  200 . As shown in  FIG.  9   , each of the suction arms  610  is angled at the end so that their longitudinal axes  900  and  902  are parallel to the EUV light paths L or L′. With such a configuration, the suction arms  610  are able to capture more gas flowing from the light source  200  (e.g., hydrogen gas) along with the contaminants, without interfering with the transmission of EUV light from the light source  200 . 
     In some embodiments of the present disclosure, the suction arms  610  (particularly the suction opening located at each of the end of the suction arms  610 ) and/or the circular gas channel  620  include the magnet member  182  to deter the contaminants such as tin debris from contaminating the components in the scanner  300  (e.g., the illuminator, the photomask stage, the projection optics, and the substrate table). As discussed above, the magnet member  182  includes one or more of a permanent magnet, an electromagnet driven by the magnet member driver  180 , or a permanent magnet and an electromagnet. As described above in  FIG.  5    and  FIG.  6   , by controlling the electromagnet (e.g., transmitting an electromagnet control signal to the magnet member driver  180 ), by arranging the permanent magnet with different magnetic power, or both, variation in the magnetic field created by the magnet member  182  increases the likelihood of diverting contaminants that are susceptible to a magnetic field to an inner surface of an inner wall of the chamber of the scanner  300  rather than allowing the contaminants to continue toward components in the scanner  300  (e.g., the illuminator, the photomask stage, the projection optics, and the substrate table). For example, electromagnets (A-H) of the magnet member  182  in  FIG.  8    can be operated similar to the electromagnets (A-H) of the magnet member  182  in  FIG.  6    to increase the likelihood of diverting the contaminants to an inner surface of a wall of the chamber of the scanner  300 . 
       FIG.  10    is a flow chart illustrating a method of a lithography process  700  implemented by the extreme ultraviolet light lithography system  100  including the hollow connection member  232  configured with the inlet  500  according to one or more embodiments of the present disclosure. 
     Method  700  includes an operation  702  by loading an EUV mask, such as mask  330  to the extreme ultraviolet light lithography system  100  that is operable to perform an EUV lithography exposing process. Mask  330  includes an IC pattern to be transferred to a semiconductor substrate, such as the substrate  350 . Operation  702  may further include various steps, such as securing the mask  330  on the photomask stage  320  and performing an alignment. 
     Method  700  includes an operation  704  by loading the substrate  350  to the extreme ultraviolet light lithography system  100 . Substrate  350  is coated with an EUV patternable material, e.g., a photoresist layer. In the present embodiment, the photoresist layer is sensitive to the EUV radiation from the light source  100  of the extreme ultraviolet light lithography system  100 . 
     Method  700  includes an operation  706  of providing suction via the inlet  500  (e.g., suction openings  510 ) within the hollow connection member  232 . As discussed above, in some embodiments, the controller  400  is configured to generate the contamination abatement module control signal based on the vacuum pressure data of the scanner  300  to keep the hollow connection member  232  under the higher vacuum condition than the vacuum condition of the scanner  300 . In some embodiments, the controller  400  transmits the contamination abatement module control signal (e.g., exhaust pump control signal) based on the vacuum pressure data of the scanner  300  to maintain the hollow connection member  232  under the higher vacuum condition than the vacuum condition in the scanner  300  by a predetermined pressure difference (e.g., 2 Pa). In some embodiments, the controller  400  is configured to vary the predetermined pressure difference (e.g., setting the predetermined pressure from the 2 Pa to 1 Pa and back to 2 Pa) to create variation in the gas flow pattern in the hollow space. The random variation (and/or the periodic variation) in the flow pattern provides a different gas flow pattern that can increase the likelihood of diverting the contaminants to the inner surface of the scanner  300  rather than allowing them to flow towards the components in the scanner  300  (e.g., the illuminator, the photomask stage, the projection optics, and the substrate table). 
     Method  700  includes an operation  708  of providing a magnetic field, using the magnet member  182 , in the hollow connection member  232 . As discussed above, in some embodiments, the hollow connection member  232  includes the magnet member  182  to create a (electro) magnetic field to attract the contaminants (e.g., tin debris) into the suction openings  510 . Some of the contaminants that are attracted to or influenced by the magnetic field but still remain in the extreme ultraviolet light lithography system  100  (e.g., the hollow connection member  232  and scanner  300 ) are diverted to the inner surface of the scanner  300  rather than flowing towards surfaces of the components in the scanner  300  (e.g., the illuminator, the photomask stage, the projection optics, and the substrate table). In some embodiments, the suction provided by operation  706  remains through the whole duration of the operation  708 . 
     Method  700  includes an operation  710  of performing a lithography exposing process on the substrate  350  in the extreme ultraviolet light lithography system  100 . In the operation  710 , the light generator  220  (e.g., carbon dioxide pulse laser generator and excimer laser generator) and the droplet generator  202  are turned on in a synchronized mode (the laser pulse and the droplet generation rate are synchronized) through a suitable mechanism, such as a control circuit (such as controller  400 ) with a timer to control and synchronize both. In some embodiments, the suction provided by the operation  706  remains in place through the whole duration of the operation  710 . In some embodiments, the magnetic field provided by the operation  708  remains in place through the whole duration of the operation  710 . In some embodiments, the variation of the operation of the exhaust pump  170  and/or the energizing of the magnet member  182  is synchronized with the operation of the light generator  220  in the droplet generator  202  so as to maximize the removal of contaminants from the extreme ultraviolet light lithography system  100 . 
     During the operation  710 , the EUV light generated by the light source  200  is illuminated on the mask  330  (by the illuminator  310 ), and is further projected on the photoresist layer coated on the substrate  350  (by the projection optics  340 ), thereby forming a latent image on the photoresist layer. In some embodiments, the lithography exposing process is implemented in a scan mode. 
     Method  700  may include other operations to complete the lithography process. For example, the method  700  may include an operation  710  of developing the exposed photoresist layer to form a photoresist pattern having a plurality of openings defined thereon. Particularly, after the lithography exposing process at the operation  710 , the substrate  350  is transferred out of the extreme ultraviolet light lithography system  100  to a developing unit to perform a developing process to the photoresist layer. Method  700  may further include other operations, such as various baking steps. As one example, the method  700  may include a post-exposure baking (PEB) step between the operations  708  and  710 . 
     Method  700  may further include other operations, such as an operation  712  to perform a fabrication process to the substrate through the openings of the photoresist pattern. In one example, the fabrication process includes an etch process to the wafer using the photoresist pattern as an etch mask. In another example, the fabrication process includes an ion implantation process to the wafer using the photoresist pattern as an implantation mask. 
       FIG.  11    is a flow chart illustrating a method of a lithography process  800  implemented by the extreme ultraviolet light lithography system  100  configured with the inlet  600  having the circular configuration described with reference to  FIGS.  7 - 9    according to one or more embodiments of the present disclosure. 
     Method  800  includes an operation  802  of loading an EUV mask, such as mask  330 , to the extreme ultraviolet light lithography system  100  that is operable to perform an EUV lithography exposing process. Mask  330  includes an IC pattern to be transferred to a semiconductor substrate, such as the substrate  350 . Operation  802  may further include various steps, such as securing the mask  330  on the photomask stage  320  and performing an alignment. 
     Method  800  includes an operation  804  of loading the substrate  350  to the extreme ultraviolet light lithography system  100 . Substrate  350  is coated with a photoresist layer. In the present embodiment, the photoresist layer is sensitive to the EUV radiation from the light source  100  of the extreme ultraviolet light lithography system  100 . 
     Method  800  includes an operation  806  of providing suction via the suction arms  610  included in the inlet  600 . As discussed above, in some embodiments, each of the suction arms  610  is connected to the exhaust pump  170  via the circular gas channel  620  arranged within the inlet  600  and the gas line  174 . Each of the suction arms  610  of the inlet is connected to the exhaust pump  170  that is configured to remove the air or gas (e.g., hydrogen gas) along with contaminants (e.g., tin debris) and/or change the flow pattern of the gas adjacent to the portion of the hollow connection member  232  adjacent to the scanner  300 . By changing the flow pattern of the gas, some of the contaminants passing the area adjacent to the portion of the hollow connection member  232  are influenced by the flow pattern created by the suction from the suction arms  610  and are diverted towards an inner surface of a wall of the chamber of the scanner  300  rather than flowing towards surfaces of the components in the scanner  300  (e.g., the illuminator, the photomask stage, the projection optics, and the substrate table). 
     Method  800  includes an operation  808  of providing a (electro) magnetic field, using the magnet member  182 , in the inlet  600 . As discussed above, in some embodiments, the inlet  600  includes the magnet member  182  which can be energized to create a (electro) magnetic field to attract contaminants (e.g., tin debris) into the suction arms  610  (e.g., inlet of the suction arms  610 ) or to change the path of contaminants that are flowing towards various components in the scanner  300 . Some of the contaminants that are attracted to or influenced by the magnetic field but still remain in the extreme ultraviolet light lithography system  100  (e.g., scanner  300 ) are diverted to the inner surface of a wall of the chamber of the scanner  300  rather continuing on toward components in the scanner  300  (e.g., the illuminator, the photomask stage, the projection optics, and the substrate table). 
     Method  800  includes an operation  810  of performing a lithography exposing process to the substrate  350  in the extreme ultraviolet light lithography system  100 . In the operation  810 , the light generator  220  (e.g., carbon dioxide pulse laser generator and excimer laser generator) and the droplet generator  202  are turned on in a synchronized mode (the laser pulse and the droplet generation rate are synchronized) through a suitable mechanism, such as a control circuit (such as controller  400 ) with a timer to control and synchronize both. In some embodiments, the suction provided by the operation  806  remains in place through the whole duration of the operation  810 . In some embodiments, the magnetic field provided by the operation  808  remains in place through the whole duration of the operation  810 . In some embodiments, the variation of the operation of the exhaust pump  170  and/or the energizing of the magnet member  182  is synchronized with the operation of the light generator  220  in the droplet generator  202  so as to maximize the removal of contaminants from the extreme ultraviolet light lithography system  100 . 
     During the operation  810 , the EUV light generated by the light source  200  is illuminated on the mask  330  (by the illuminator  310 ), and is further projected on the photoresist layer coated on the substrate  350  (by the projection optics  340 ), thereby forming a latent image on the photoresist layer. In some embodiments, the lithography exposing process is implemented in a scan mode. 
     Method  800  may include other operations to complete the lithography process. For example, the method  800  may include an operation  810  of developing the exposed photoresist layer to form a photoresist pattern having a plurality of openings defined thereon. Particularly, after the lithography exposing process at the operation  810 , the substrate  350  is transferred out of the extreme ultraviolet light lithography system  100  to a developing unit to perform a developing process to the photoresist layer. Method  800  may further include other operations, such as various baking steps. As one example, the method  800  may include a post-exposure baking (PEB) step between the operations  808  and  810 . 
     Method  800  may further include other operations, such as an operation  812  to perform a fabrication process to the substrate through the openings of the photoresist pattern. In one example, the fabrication process includes an etch process to the wafer using the photoresist pattern as an etch mask. In another example, the fabrication process includes an ion implantation process to the wafer using the photoresist pattern as an implantation mask. 
     Utilizing contamination abatement module  160  that is able to reduce volume of contaminants that impinge and accumulate on components of the scanner  300 , such as the tin debris entering into the scanner  300 , will produce a substantial fabrication cost savings due to reduced defects in the exposure step. 
     Utilizing contamination abatement module  160  that is able to reduce the volume of contaminants that impinge and accumulate on components of the scanner  300 , such as the tin debris entering into the scanner  300 , will extend the cleaning interval (e.g., preventive maintenance interval) of various components in the scanner  300 . 
     Utilizing contamination abatement module  160  that is able to reduce the contaminants that impinge and accumulate on components of the scanner  300 , such as the tin debris entering into the scanner  300 , will improve or maintain the intensity of the extreme ultraviolet light provided to the scanner  300  of the extreme ultraviolet light lithography system  100 . By maintaining the intensity of the extreme ultraviolet light provided to the scanner  300 , the quality of the patterns produced in the photoresist will be maintained within process tolerances. 
     According to one or more embodiments of the present disclosure, a lithography system is provided capable of deterring the contaminants such as tin debris from entering into a scanner of the lithography system. The lithography system in accordance with various embodiments of the present disclosure includes a processor, an extreme ultraviolet light source, a scanner, and a hollow connection member. The extreme ultraviolet light source includes a droplet generator for generating a droplet, a collector for reflecting extreme ultraviolet light into an intermediate focus point, and a light generator for generating pre-pulse light and main pulse light, wherein the droplet generates the extreme ultraviolet light in response to the droplet being illuminated with the pre-pulse light and the main pulse light. The scanner includes a mask stage and a substrate table. The hollow connection member includes an inlet in fluid communication with an exhaust pump. The hollow connection member includes a hollow space in which the intermediate focus point is disposed. The hollow connection member is disposed between the extreme ultraviolet light source and the scanner. 
     According to one or more embodiments of the present disclosure, a method of generating extreme ultraviolet light for a semiconductor fabrication process includes determining, by a processor, an operation parameter of an exhaust pump. The determining the operation parameter of the exhaust pump includes measuring vacuum pressure in a scanner of a lithography system and determining a speed at which to operate the exhaust pump based on the vacuum pressure in the scanner. The pump is in fluid communication with a hollow connection member between the scanner and a light source of the lithography system. 
     According to one or more embodiments of the present disclosure, a method of generating extreme ultraviolet light for a semiconductor fabrication process includes loading the mask in an extreme ultraviolet light lithography system, operating the exhaust pump, and exposing the mask to extreme ultraviolet light from the extreme ultraviolet light source. The extreme ultraviolet light lithography system includes a processor, an extreme ultraviolet light source, a scanner, and a hollow connection member. The extreme ultraviolet light source includes a droplet generator for generating a droplet, a collector for reflecting extreme ultraviolet light into an intermediate focus point, and a light generator. The scanner includes a mask stage configured to secure the mask and a substrate table configured to secure a substrate. The hollow connection member is located between the extreme ultraviolet light source and the scanner. The hollow connection member includes an inlet that is in fluid communication with an exhaust pump. The hollow connection member has a hollow space in which the intermediate focus point is disposed. 
     The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.