Abstract: Impurities in a liquefied solid fuel utilized in a droplet generator of an extreme ultraviolet photolithography system are removed from vessels containing the liquefied solid fuel. Removal of the impurities increases the stability and predictability of droplet formation which positively impacts wafer yield and droplet generator lifetime.

Abstract: The present disclosure is directed to a modularized vessel droplet generator assembly (MGDVA) including a droplet generator assembly (DGA). Under a normal operation, the liquid fuel moves along an operation pathway extending through the DGA to eject or discharge the liquid fuel (e.g., liquid tin) from a nozzle of the DGA into a vacuum chamber. The liquid fuel in the vacuum chamber is then exposed to a laser generating an extreme ultra-violet (EUV) light. Under a service operation, the operation pathway is closed and a service pathway extending through the DGA is opened. A gas is introduced into the service pathway forming a gas-liquid interface between the gas and the liquid fuel. The gas-liquid interface is driven to an isolation valve directly adjacent to the DGA. In other words, the gas pushes back the liquid fuel to the isolation valve. Once the gas-liquid interface reaches the isolation valve, the isolation valve is closed isolating the DGA from the liquid fuel.

Abstract: An extreme ultraviolet (EUV) photolithography system generates EUV light by irradiating droplets with a laser. The system includes a droplet generator with a nozzle and a piezoelectric structure coupled to the nozzle. The generator outputs groups of droplets. A control system applies a voltage waveform to the piezoelectric structure while the nozzle outputs the group of droplets. The waveform causes the droplets of the group to have a spread of velocities that results in the droplets coalescing into a single droplet prior to being irradiated by the laser.

Abstract: A method for using an extreme ultraviolet radiation source is provided. The method includes assembling a first droplet generator onto a port of a vessel; ejecting a target droplet from the first droplet generator to a zone of excitation in front of a collector; emitting a laser toward the zone of excitation, such that the target droplet is heated by the laser to generate extreme ultraviolet (EUV) radiation; stopping the ejection of the target droplet; after stopping the ejection of the target droplet, disassembling the first droplet generator from the port of the vessel; after disassembling the first droplet generator from the port of the vessel, inserting a cleaning device into the vessel through the port; and cleaning the collector by using the cleaning device.

Abstract: A photolithography system utilizes tin droplets to generate extreme ultraviolet radiation for photolithography. The photolithography system irradiates the droplets with a laser. The droplets become energized and emit extreme ultraviolet radiation. A collector reflects the extreme ultraviolet radiation toward a photolithography target. The photolithography system isolates a source of droplets from oxidants to prevent the oxidation of the nozzle or the formation of metal oxides on the nozzle, both of which can adversely affect an ability of the nozzle to generate a sufficient amount of droplets and/or direct the droplets in a desired direction.

Abstract: A droplet generator assembly includes a storage tank, a refill system, a droplet generator, and a temperature control system. The storage tank is configured to store a target material. The refill system is connected to the storage tank. The droplet generator includes a reservoir and a nozzle connected to the reservoir, in which the droplet generator is connected to the refill system, and the refill system is configured to deliver the target material to the reservoir. The temperature control system is adjacent to the refill system or the reservoir.

Abstract: A method includes providing a plurality of fuel droplets into an EUV source vessel by a fuel droplet generator, in which the fuel droplet generator has a first portion inside the EUV source vessel and a second portion outside the EUV source vessel; generating a plurality of output signals respectively from a plurality of oscillation sensors on the fuel droplet generator; determining whether the output signals are acceptable; and determining whether an unwanted oscillation originates from the first portion of the fuel droplet generator or the second portion of the fuel droplet generator when the output signals is determined as unacceptable.

Abstract: A method includes providing a plurality of fuel droplets into an EUV source vessel by a fuel droplet generator, in which the fuel droplet generator has a first portion inside the EUV source vessel and a second portion outside the EUV source vessel; generating a plurality of output signals respectively from a plurality of oscillation sensors on the fuel droplet generator; determining whether the output signals are acceptable; and determining whether an unwanted oscillation originates from the first portion of the fuel droplet generator or the second portion of the fuel droplet generator when the output signals is determined as unacceptable.

Abstract: A method includes providing a plurality of fuel droplets into an EUV source vessel by a fuel droplet generator, in which the fuel droplet generator has a first portion inside the EUV source vessel and a second portion outside the EUV source vessel; generating a plurality of output signals respectively from a plurality of oscillation sensors on the fuel droplet generator; determining whether the output signals are acceptable; and determining whether an unwanted oscillation originates from the first portion of the fuel droplet generator or the second portion of the fuel droplet generator when the output signals is determined as unacceptable.

Abstract: A droplet generator assembly includes a storage tank, a refill system, a droplet generator, and a temperature control system. The storage tank is configured to store a target material. The refill system is connected to the storage tank. The droplet generator includes a reservoir and a nozzle connected to the reservoir, in which the droplet generator is connected to the refill system, and the refill system is configured to deliver the target material to the reservoir. The temperature control system is adjacent to the refill system or the reservoir.

Abstract: A method for generating a radiation light in a lithography exposure system. The method includes producing a predetermined gas pressure in a storage chamber to supply a first load of a target fuel in the storage chamber via a nozzle. The method further includes irradiating the target fuel from the nozzle with a laser to generate the radiation light. The method also includes increasing the gas pressure in a buffer chamber which receives a second load of target fuel to the predetermined gas pressure. In addition, the method includes actuating the flow of the target fuel from the buffer chamber to the storage chamber.

Abstract: A method for generating a radiation light in a lithography exposure system. The method includes producing a predetermined gas pressure in a storage chamber to supply a first load of a target fuel in the storage chamber via a nozzle. The method further includes irradiating the target fuel from the nozzle with a laser to generate the radiation light. The method also includes increasing the gas pressure in a buffer chamber which receives a second load of target fuel to the predetermined gas pressure. In addition, the method includes actuating the flow of the target fuel from the buffer chamber to the storage chamber.

Abstract: A solar cell includes a semiconductor substrate, a back electrode layer and a front electrode layer including a first bus bar, a second bus bar, first finger bar units, second finger bar units, first interconnecting bars, and second interconnecting bars. The first finger bar units are spaced apart from the second finger bar units. Each of the first finger bar units has first finger bars and a first auxiliary bar connected to the first finger bars. Each of the second finger bar units has second finger bars and a second auxiliary bar connected to the second finger bars. Each first interconnecting bar interconnects two adjacent first finger bar units. Each second interconnecting bar interconnects two adjacent second finger bar units.