Abstract: A target droplet source for an extreme ultraviolet (EUV) source includes a droplet generator configured to generate target droplets of a given material. The droplet generator includes a nozzle configured to supply the target droplets in a space enclosed by a chamber. The target droplet source further includes a sleeve disposed in the chamber distal to the nozzle. The sleeve is configured to provide a path for the target droplets in the chamber.

Abstract: A method for performing a lithography process is provided. The method includes forming a photoresist layer over a substrate, providing a plurality of target droplets to a source vessel, and providing a plurality of first laser pulses according to a control signal provided by a controller to irradiate the target droplets in the source vessel to generate plasma as an EUV radiation. The plasma is generated when the control signal indicates a temperature of the source vessel is within a temperature threshold value. The method further includes directing the EUV radiation from the source vessel to the photoresist layer to form a patterned photoresist layer and developing and etching the patterned photoresist layer to form a circuit layout.

Abstract: A method of lithography process is provided. The method includes forming a conductive layer over a reticle. The method includes applying ionized particles to the reticle by a discharging device. The method includes forming a photoresist layer over a semiconductor substrate. The method includes securing the semiconductor substrate by a wafer electrostatic-clamp. The method also includes patterning the photoresist layer by emitting radiation from a radiation source via the reticle.

Abstract: A method includes irradiating a target droplet in an extreme ultraviolet light source of an extreme ultraviolet lithography tool with light from a droplet illumination module. Light reflected and/or scattered by the target droplet is detected. Particle image velocimetry is performed to monitor one or more flow parameters inside the extreme ultraviolet light source.

Abstract: A system is provided. The system includes an exposing device configured to generate a real-time image, including multiple first align marks, of a mask and an adjusting device configured to adjust an off-set of the mask from a pre-determined position to be smaller than a minimum aligning distance according to the first align marks and multiple align marks on a substrate, and further to move the mask closer to the pre-determined position to have a displacement, less than a minimum mapping distance, from the pre-determined position according to the real-time image and a reference image of the mask.

Abstract: A system includes a laser source operable to provide a laser beam, a laser amplifier having a gain medium operable to provide energy to the laser beam when the laser beam passes through the laser amplifier, and a residual gain monitor operable to provide a probe beam and operable to derive a residual gain of the laser amplifier from the probe beam when the probe beam passes through the laser amplifier while being offset from the laser beam in time or in path.

Abstract: Methods of fabricating and using an overlay mark are provided. In some embodiments, the overlay mark includes an upper layer and a lower layer disposed below the upper layer. The lower layer includes a first plurality of compound gratings extending in a first direction and disposed in a first region of the overlay mark, each of the first plurality of compound gratings including one first element and at least two second elements disposed on one side of the first element, and a second plurality of compound gratings extending the first direction and disposed in a second region of the overlay mark, each of the second plurality of compound gratings including one third element and at least two fourth elements on one side of the third element. The first plurality of compound gratings is a mirror image of the second plurality of compound gratings.

Abstract: A method for generating EUV light includes providing a laser beam having a Gaussian distribution. This laser beam can be then modified from a Gaussian distribution to a ring-like distribution. The modified laser beam is provided through an aperture in a collector and interfaces with a moving droplet target, which generates an extreme ultraviolet (EUV) wavelength light. The generated EUV wavelength light is provided to the collector away from the aperture. In some embodiments, a mask element may also be used to modify the laser beam to a shape.

Abstract: A light source for EUV radiation is provided. The light source includes a target droplet generator, a laser generator, and a controller. The target droplet generator is configured to provide target droplets to a source vessel. The laser generator is configured to provide a plurality of first laser pulses according to a control signal to irradiate the target droplets in the source vessel to generate plasma as the EUV radiation. The controller is configured to provide the control signal according to the temperature of the source vessel and droplet positions of the target droplets. When the temperature of the source vessel exceeds a temperature threshold value and a standard deviation of the droplet positions of the target droplets exceeds a first standard deviation threshold value, the controller is configured to provide the control signal to the laser generator, so as to stop providing the first laser pulses.

Abstract: A reticle, a reticle container and a method of lithography process are provided. The reticle container includes: a cover configured to protect a reticle, a baseplate, and a discharging device on the baseplate. The baseplate has: a top surface configured to engage to the cover and a bottom surface opposite to the top surface. The discharging device is configured to neutralize static charges accumulated on the reticle.

Abstract: The present disclosure provides a method for aligning a master oscillator power amplifier (MOPA) system. The method includes ramping up a pumping power input into a laser amplifier chain of the MOPA system until the pumping power input reaches an operational pumping power input level; adjusting a seed laser power output of a seed laser of the MOPA system until the seed laser power output is at a first level below an operational seed laser power output level; and performing a first optical alignment process to the MOPA system while the pumping power input is at the operational pumping power input level, the seed laser power output is at the first level, and the MOPA system reaches a steady operational thermal state.

Abstract: A method includes irradiating a target droplet in an extreme ultraviolet light source of an extreme ultraviolet lithography tool with light from a droplet illumination module. Light reflected and/or scattered by the target droplet is detected. Particle image velocimetry is performed to monitor one or more flow parameters inside the extreme ultraviolet light source.

Abstract: A control system includes a plurality of pressure sensors, each to detect a pressure in a respective dynamic gas lock (DGL) nozzle control region of a plurality of DGL nozzle control regions. Each DGL nozzle control region includes one or more DGL nozzles. The control system includes a plurality of mass flow controllers (MFCs). Each MFC of the plurality of MFCs is to control a flow velocity in a respective DGL nozzle control region of the plurality of DGL nozzle control regions. The control system includes a controller to selectively cause one or more MFCs of the plurality of MFCs to adjust flow velocities in one or more DGL nozzle control regions of the plurality of DGL nozzle control regions based on pressures detected by the plurality of pressure sensors in DGL nozzle control regions of the plurality of DGL nozzle control regions.

Abstract: A system is disclosed. The system includes a cleaning device and a scanner device. The cleaning device is configured to clean a mask. The scanner device is coupled to the cleaning device and is configured to receive the mask, a reference image and a real-time image that is captured at the mask. The reference image includes at least one first mark image having a plurality of mapping marks on the mask. The real-time image includes at least one second mark image having the plurality of mapping marks on the mask. The scanner device is configured to map the at least one second mark image in the real-time image with the at least one first image in the reference image, when a lithography exposing process is performed. A method is also disclosed herein.

Abstract: A method of inspecting a reticle includes obtaining a first image of a surface of the reticle at a first height by scanning the reticle surface with a light source at the first height of the reticle surface relative to a reference surface height of the reticle surface and obtaining a second image of the reticle surface at a second height by scanning the reticle surface with the light source at the second height of the reticle surface relative to the reference surface height of the reticle surface. The second height is different from the first height. The first and the second images are then combined to obtain a surface profile image of the reticle.

Abstract: A method for performing DBO measurements utilizing apertures having a single pole includes using a first aperture plate to measure X-axis diffraction of a composite grating. In some embodiments, the first aperture plate has a first pair of radiation-transmitting regions disposed along a first diametrical axis and on opposite sides of an optical axis that is aligned with a center of the first aperture plate. Thereafter, in some embodiments, a second aperture plate, which is complementary to the first aperture plate, is used to measure Y-axis diffraction of the composite grating. By way of example, the second aperture plate has a second pair of radiation-transmitting regions disposed along a second diametrical axis and on opposite sides of the optical axis. In some cases, the second diametrical axis is substantially perpendicular to the first diametrical axis.

Abstract: A method for lithography in semiconductor fabrication is provided. The method includes placing a semiconductor wafer over a wafer stage. The method also includes supplying an initial voltage to a plurality of electrodes of the wafer stage based on a topology of the semiconductor wafer, wherein the electrodes of the wafer stage are electrically isolated from each other. The method further includes measuring an adjusted topology of the semiconductor wafer after the initial voltage is supplied. In addition, the method includes supplying different first adjusted voltages to the electrodes of the wafer stage according to the adjusted topology of the semiconductor wafer.

Abstract: An apparatus for generating extreme ultraviolet (EUV) radiation includes a droplet generator configured to generate target droplets. An excitation laser is configured to heat the target droplets using excitation pulses to convert the target droplets to plasma. An energy detector is configured to measure a variation in EUV energy generated when the target droplets are converted to plasma. A feedback controller is configured to adjust parameters of the droplet generator and/or the excitation laser based on the variation in EUV energy.

Abstract: A method includes following steps. A photoresist-coated substrate is received to an extreme ultraviolet (EUV) tool. An EUV radiation is directed from a radiation source onto the photoresist-coated substrate, wherein the EUV radiation is generated by an excitation laser hitting a plurality of target droplets ejected from a first droplet generator. The first droplet generator is replaced with a second droplet generator at a temperature not lower than about 150° C.

Abstract: A droplet generator for an extreme ultraviolet imaging tool includes a reservoir for a molten metal, and a nozzle having a first end connected to the reservoir and a second opposing end where molten metal droplets emerge from the nozzle. A gas inlet is connected to the nozzle, and an isolation valve is at the second end of the nozzle configured to seal the nozzle droplet generator from the ambient.