TW201337470A - Radiation source and method for lithographic apparatus and device manufacture - Google Patents

Abstract

A method of treating or operating a radiation source apparatus, for instance for generating EUV radiation for device lithography, is disclosed. The method is for use with radiation source apparatus having a chamber arranged to hold a plasma for radiation generation, with the plasma excited from a metal fuel in use by a first plasma generator. The method comprises flowing a gas comprising hydrogen and boron hydride through the chamber with the gas in an excited state comprising free radicals of hydrogen. The presence of the boron hydride with the hydrogen radicals in the gas is effective cleaning or reducing build-up of metal fuel deposits on surfaces of the chamber or associated optics, particularly on reflective surfaces of the radiation collector mirror. The method is particularly suitable for use with tin fuel. The hydrogen free radicals may be generated by the plasma for radiation generation itself, or may involve exciting the gas using a second, separate free radical generator. The method may be used to reduce deposition whilst the radiation source apparatus is in use for generation of radiation or may be applied as a treatment for cleaning whilst radiation generation is interrupted.

Description

Radiation source and method for lithography apparatus and component manufacturing

The present invention relates to methods for processing and/or operating radiation sources, such as EUV radiation sources for use in lithography, and lithographic apparatus and methods for fabricating components using radiation sources.

The present application claims the benefit of U.S. Provisional Application No. 61/579,974, filed on Dec. 23, 2011, the entire disclosure of which is incorporated herein by reference.

A lithography apparatus is a machine that applies a desired pattern onto a substrate, typically applied to a target portion of the substrate. The lithography apparatus can be used, for example, in the fabrication of integrated circuits (ICs). In that case, a patterned element (which may be referred to as a reticle or a proportional reticle) may be used to create a circuit pattern to be formed on individual layers of the IC. This pattern can be transferred onto a target portion (eg, a portion containing a die, a die, or a plurality of dies) on a substrate (eg, a germanium wafer). Transfer of the pattern is typically performed via imaging onto a layer of radiation-sensitive material (resist) provided on the substrate. In general, a single substrate will contain a network of sequentially adjacent adjacent target portions.

Photolithography is widely recognized as one of the key steps in the manufacture of ICs and other components and/or structures. However, as the dimensions of features fabricated using lithography become smaller and smaller, lithography is becoming a more decisive factor for enabling the fabrication of small ICs or other components and/or structures.

The theoretical estimate of the pattern printing limit can be given by the Rayleigh resolution criterion, as shown in equation (1): Where λ is the wavelength of the radiation used, NA is the numerical aperture of the projection system used to print the pattern, k1 is the program dependent adjustment factor (also known as the Rayleigh constant), and CD is the characteristic size of the printed features (or Critical dimension). It can be seen from equation (1) that the reduction in the minimum printable size of the feature can be obtained in three ways: by shortening the exposure wavelength λ, by increasing the numerical aperture NA, or by reducing the value of k ₁ .

In order to shorten the exposure wavelength and thus reduce the minimum printable size, it has been proposed to use an extreme ultraviolet (EUV) radiation source. The EUV radiation is electromagnetic radiation having a wavelength in the range of 5 nm to 20 nm (for example, in the range of 13 nm to 14 nm). It has further been proposed to use EUV radiation having a wavelength of less than 10 nanometers (e.g., in the range of 5 nanometers to 10 nanometers, such as 6.7 nanometers or 6.8 nanometers). This radiation is called extreme ultraviolet radiation or soft x-ray radiation. By way of example, possible sources include a laser generating plasma source, a discharge plasma source, or a source based on synchrotron radiation provided by an electronic storage ring.

Plasma can be used to generate EUV radiation. A radiation source device for generating EUV radiation may include a laser for exciting a fuel to provide a plasma, and a source collector device for containing the plasma. Plasma can be created, for example, by directing a laser beam at a fuel, such as particles of a suitable material, or a suitable gas or vapor stream. Typically, the fuel can be a metal fuel such as lithium or tin. The resulting plasma emits output radiation, such as EUV radiation, which is collected using a radiation collector that forms a component of the radiation source device. The radiation collector can be a mirrored normal incidence radiation collector that receives the radiation and focuses the radiation into a beam of light. The radiation source device can include a vacuum or low pressure configured to provide The environment supports the enclosing structure or chamber of the plasma. This source device is commonly referred to as a laser generated plasma (LPP) source.

Discharge-generating plasma (DPP) radiation originates from plasma generated by electrical discharge to generate radiation, such as extreme ultraviolet radiation (EUV), and may in particular involve high temperature vaporization of the metal fuel to direct such as laser light toward the metal fuel. The excitation beam of the beam produces radiation. A metal, typically in molten form, can be supplied to the discharge surface of the plasma excitation electrode and vaporized by irradiation with an excitation beam such as a laser beam, whereby it can then be discharged by high voltage across the electrodes. Self-vaporizing metal fuel excites high temperature plasma.

The DPP radiation source device can include a containment structure or chamber configured to provide a vacuum or low pressure environment to support the plasma. The resulting plasma emits output radiation, such as EUV radiation, which is collected using a radiation collector that forms a component of the radiation source device, such as a mirrored normal incidence radiation collector. In this case, the radiation source device may be referred to as a source collector device.

As used herein, the term vaporization is also considered to include gasification, and the fuel after vaporization may be in the form of a gas (eg, as an individual atom) and/or a vapor (including droplets). The term "particle" as used herein includes both solid particles and liquid (ie, droplet) particles.

For EUV radiation source devices such as those set forth above (where the radiation is generated from the plasma excited by the metal fuel), the problem arises: metal fuel can be deposited and accumulated on the internal surface of the device, such as holding The interior of the chamber of the plasma and the mirrored surface of the radiation collector.

Detrital particles of metal fuel can be produced as undesirable by-products of radiation, and such debris particles and vaporized/gas-like from the plasma The metal fuel can be deposited on the interior surface of the radiation source device and in particular on the radiation collector.

Finally, it may become necessary to clean the interior surface of the radiation source device, particularly the mirrored radiation collector surface. There is a need to maximize the period during which the radiation source device can be used to generate radiation between such cleaning procedures. There is also a need to minimize the amount of metal fuel deposited on the interior surface of the radiation source device, particularly on the mirrored surface of the radiation collector. It is also necessary to clean the deposited metal fuel without removing the radiation source device.

Accordingly, there is a need to provide a method for processing or operating a radiation source device that produces radiation, such as EUV radiation, from a plasma that is excited from a metal fuel in order to address the above discussed problems and others.

One aspect of the present invention provides a method of processing or operating a radiation source device, the device comprising a chamber configured to hold one of the plasmas for radiation generation, wherein the plasma system is first The plasma generator is excited from a metal fuel, the method comprising flowing a gas comprising hydrogen and boron hydride through the chamber, wherein the gas in an excited state comprises hydrogen radicals (also in the form of a simplified form herein) "In the case of a gas in an excited state" mentioned).

The chamber will be substantially closed, but apertures may typically be present therein to allow radiation generated by the radiation source device to exit from the radiation source device to an optical system of a lithography apparatus.

The first plasma generator can be any suitable plasma generator, such as one of the laser generated plasma sources or a discharge generated plasma source as described herein. The The metal fuel can be any suitable metal fuel used to produce a plasma to produce radiation such as EUV radiation. Typical fuels include lithium and tin.

The gas can flow through the chamber through an inlet orifice and exit the chamber through an outlet orifice wherein the gas system comprising boron hydride and hydrogen is supplied in a premixed state. In another suitable configuration, the hydrogen and the boron hydride may be separately supplied to the chamber as a separate gas stream, and may be mixed into the chamber, for example, by diffusion or by other means. In the room.

The gas can be excited by the first plasma generator to form hydrogen radicals during use. Thus, the first plasma generator can also act as a first free radical generator when the device is used to generate radiation.

The radiation source device can, for example, be a laser generated plasma device, wherein the first plasma generator includes a laser beam that is directed to the metal fuel. This first plasma generator can also generate hydrogen radicals in the gas.

Alternatively or additionally, the gas may be excited by a second radical generator that is separate from the first plasma generator to form hydrogen radicals. For example, the gas containing hydrogen and boron hydride may be flowed through the chamber when the device is not used to generate radiation (eg, wherein the first plasma source is not turned on), and then, the device is used The gas comprising hydrogen and boron hydride is replaced with an operating gas prior to use in generating the radiation. The operating gas can be, for example, an inert gas such as argon or, for example, hydrogen without boron hydride such as pure hydrogen.

The second radical generator can be any suitable component for generating hydrogen radicals from the gas and can be located within the chamber or outside of the chamber. For example The second radical generator may comprise a second plasma generator for generating a second plasma for exciting free radicals. The second radical generator can be selected from the group consisting of a thermal cracker, an inductively coupled plasma generator, and a microwave plasma generator. It will be apparent that for a second radical generator that is a plasma generator, the hydrogen radicals will be generated by the second plasma produced by the plasma generator, or by radiation from the second plasma. produce.

The gas may be excited by the second radical generator to form a hydrogen radical before the gas enters the chamber (eg, at a location in or near a gas inlet orifice) such that it may be in the chamber External excitation of hydrogen radicals takes place in the gas, and then the radicals flow into the chamber with the gas.

The gas in an excited state can flow through the chamber when the radiation source device is not used to generate radiation.

The radiation source device can be a discharge generated plasma (DPP) device, wherein the first plasma generator includes a laser beam directed to the metal fuel to produce a metal fuel vapor, and configured to be The metal fuel vapor is discharged to produce one of the plasmas for radiation generation to the discharge electrode.

The gas in an excited state can be directed to flow across a reflective surface of one of the radiation collectors within the chamber. This can be achieved by using a nozzle or vane to direct the flow, for example, within the chamber.

The gas flowing through the chamber may comprise hydrogen from 10 Pascal to 500 Pascal partial pressure, for example, from 50 Pascals to 200 Pascals, and comprises boron hydride from 0.1 Pascal to 5 Pascal partial pressure, such as from 0.5 Pascals. Up to 2 Pascals.

The gas may suitably consist essentially of hydrogen and boron hydride, which means that other gases or vapors are not intentionally added to the gas, but merely as naturally occurring impurities at, for example, a partial pressure of less than, for example, 0.05 Pascals. And exist.

In the present specification, the partial pressure is measured at 25 °C.

For a chamber having one volume of 1000 liters, the flow rate of the gas through the chamber of the radiation source device is suitably in the range of 50 to 1000 standard liters per minute, for example, 60 to 500 standards per minute. Liters, such as 80 to 200 standard liters per minute. For chambers of different volumes, the appropriate flow rate can be determined proportionally.

Suitably, the metal fuel is a tin fuel, which means that the fuel consists essentially of tin, wherein other elements are present as naturally occurring impurities, for example, wherein the non-tin element is 1% by weight or less and less than 1% by weight. The total level exists.

One aspect of the present invention also provides a method of processing or operating a radiation source device, the device comprising a chamber configured to hold one of the plasmas for radiation generation, the plasma system being first used by the plasma system The plasma generator is energized from a metal fuel, the method comprising flowing a gas comprising hydrogen gas through the chamber, wherein the gas system is excited by a second radical generator to form hydrogen radicals. The second radical generator can be as described above with respect to the previous aspects of the invention.

One aspect of the present invention provides a component manufacturing method including projecting a patterned radiation beam onto a substrate, wherein the antenna The beam of light is generated using a radiation source device comprising a chamber configured to hold one of the plasmas for radiation generation, the plasma system for radiation generation being used as an excitation radiation One of the beams of the first plasma generator is excited from a metal fuel, the method comprising flowing a gas comprising hydrogen and boron hydride through the chamber, wherein when used for the generation of radiation, the gas system is used for radiation The plasma generated is excited to generate hydrogen radicals.

The excitation radiation beam may suitably be a laser beam and may, for example, be focused onto the metal fuel source to form the plasma. The excitation radiation beam thus acts as a first plasma generator for this aspect of the invention, and the resulting plasma is also used to form hydrogen radicals from the gas source when it is operated to generate radiation such as EUV radiation.

One aspect of the present invention provides a lithography apparatus comprising: an illumination system configured to adjust a radiation beam; a support member configured to support a patterned component, the patterned component A pattern can be imparted to the radiation beam in a cross section of the radiation beam to form a patterned radiation beam; a substrate stage configured to hold a substrate; and a projection system configured to pattern the pattern The radiation beam is projected onto a target portion of the substrate. The illumination system includes a radiation source device including a first plasma generator and a chamber configured to hold one of the plasmas for radiation generation, the plasma system being used by the first The plasma generator is excited from a metal fuel. The lithography apparatus further includes means for flowing a gas comprising hydrogen gas through one of the chambers, and configured to excite the gas to generate hydrogen radicals in the gas flowing through the chamber One of the second free radical generators.

Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail herein. It should be noted that the invention is not limited to the specific embodiments described herein. These embodiments are presented herein for illustrative purposes only. Additional embodiments will be apparent to those skilled in the art in view of the teachings herein.

The present invention is described in the accompanying drawings, and in the claims

The features and advantages of the present invention will become more apparent from the <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; In the drawings, like element symbols generally indicate equivalent, functionally similar, and/or structurally similar devices. The pattern of the first occurrence of a device is indicated by the leftmost digit of the corresponding component symbol.

This description discloses one or more embodiments that incorporate the features of the invention. The disclosed embodiments are merely illustrative of the invention. The scope of the invention is not limited to the disclosed embodiments. The invention is defined by the scope of the patent application appended hereto.

The described embodiments and the reference to the "an embodiment", "an example embodiment" and the like in the specification may include a specific feature, structure or characteristic, but each embodiment may not necessarily include the A specific feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Additionally, a particular feature, structure, or characteristic is described in connection with an embodiment. It is to be understood that the features, structures, or characteristics of the present invention are to be understood by those skilled in the art, whether or not explicitly described.

Embodiments of the invention may be implemented in hardware, firmware, software, or any combination thereof. Embodiments of the invention may also be implemented as instructions stored on a machine-readable medium, which may be read and executed by one or more processors. A machine-readable medium can include any mechanism for storing or transmitting information in a form readable by a machine (eg, a computing element). By way of example, a machine-readable medium can include: read only memory (ROM); random access memory (RAM); disk storage media; optical storage media; flash memory components; electrical, optical, acoustic, or other Formal propagation signals (eg, carrier waves, infrared signals, digital signals, etc.); and others. Additionally, firmware, software, routines, instructions may be described herein as performing certain actions. It should be understood, however, that the description is only for convenience, and such acts are in fact caused by computing elements, processors, controllers, or other components that perform firmware, software, routines, instructions, and the like.

However, it is intended to present an example environment in which embodiments of the invention may be practiced.

FIG. 1 schematically shows a lithography apparatus LAP including a source collector module SO in accordance with an embodiment of the present invention. The apparatus includes a lighting system (illuminator) IL configured to condition a radiation beam B (eg, EUV radiation), and a support structure (eg, a reticle stage) MT configured to support the patterned element (eg, a reticle or proportional reticle) MA and coupled to a first locator PM configured to accurately position the patterned component; a substrate stage (eg, a wafer a WT that is configured to hold a substrate (eg, a resist coated wafer) W and is coupled to a second locator PW configured to accurately position the substrate; and a projection system (eg, a reflective projection) A system) PS configured to project a pattern imparted by the patterned element MA to the radiation beam B onto a target portion C of the substrate W (eg, comprising one or more dies).

The illumination system can include various types of optical components for guiding, shaping, or controlling radiation, such as refractive, reflective, magnetic, electromagnetic, electrostatic, or other types of optical components, or any combination thereof.

The support structure MT holds the patterned element in a manner that depends on the orientation of the patterned element MA, the design of the lithography apparatus, and other conditions, such as whether the patterned element is held in a vacuum environment. The support structure can use mechanical, vacuum, electrostatic or other clamping techniques to hold the patterned elements. The support structure can be, for example, a frame or table that can be fixed or movable as desired. The support structure can ensure that the patterned element is, for example, in a desired position relative to the projection system.

The term "patterned element" should be interpreted broadly to refer to any element that can be used to impart a pattern to a radiation beam in a cross-section of a radiation beam to create a pattern in a target portion of the substrate. The pattern imparted to the radiation beam may correspond to a particular functional layer in an element (such as an integrated circuit) created in the target portion.

The patterned elements can be transmissive or reflective. Examples of patterned components include photomasks, programmable mirror arrays, and programmable LCD panels. Photomasks are well known in lithography and include reticle types such as binary, alternating phase shift and attenuated phase shift, as well as various hybrid mask types. Programmable mirror One example of a face array uses a matrix configuration of small mirrors, each of which can be individually tilted to reflect the incident radiation beam in different directions. The tilted mirror imparts a pattern in the radiation beam reflected by the mirror matrix.

Similar to an illumination system, the projection system can include various types of optical components suitable for the exposure radiation used or other factors such as the use of vacuum, such as refractive, reflective, magnetic, electromagnetic, electrostatic or other types of optical components. , or any combination thereof. Vacuum may be required for EUV radiation because other gases may absorb excessive radiation. Therefore, a vacuum environment or a low pressure environment can be supplied to a partial beam path by means of a vacuum wall and a vacuum pump.

As depicted herein, the device is of the reflective type (eg, using a reflective mask).

The lithography device can be of the type having two (dual stage) or more than two substrate stages (and/or two or more reticle stages). In such "multi-stage" machines, additional stations may be used in parallel, or preliminary steps may be performed on one or more stations while one or more other stations are used for exposure.

Referring to Figure 1, illuminator IL receives a beam of extreme ultraviolet radiation from source collector device SO. Methods for producing EUV light include, but are not necessarily limited to, converting a material having at least one element (eg, lithium or tin) into a plasma state using one or more emission lines in the EUV range. In one such method (often referred to as laser-generated plasma "LPP"), the fuel can be irradiated with a laser beam (such as droplets, streams, or materials with desired spectral line emission elements). Cluster) to produce the desired plasma. The source collector device SO can be a component of an EUV radiation system including a laser (not shown in Figure 1) for providing a laser beam that excites the fuel. The resulting plasma emits output radiation, such as EUV radiation, which is collected using a radiation collector disposed in the source collector device. For example, when using a CO ₂ laser for providing the laser beam when the excitation of the fuel, and a laser source may be a separate collector means entities. The laser beam can be delivered from the laser to the source collector device by means of a beam delivery system comprising, for example, a suitable guiding mirror and/or beam expander. In other cases, for example, when the source is a discharge producing a plasma EUV generator (often referred to as a DPP source), the source can be an integral part of the source collector device.

The illuminator IL can include an adjuster for adjusting the angular intensity distribution of the radiation beam. In general, at least the outer radial extent and/or the inner radial extent (commonly referred to as σ outer and σ inner, respectively) of the intensity distribution in the pupil plane of the illuminator can be adjusted. Additionally, illuminator IL can include various other components, such as faceted field mirror elements and faceted mirror elements. The illuminator can be used to adjust the radiation beam to have a desired uniformity and intensity distribution in its cross section.

The radiation beam B is incident on a patterned element (e.g., reticle) MA that is held on a support structure (e.g., a reticle stage) MT, and is patterned by the patterned element. After being reflected from the patterned element (e.g., reticle) MA, the radiation beam B is passed through a projection system PS that focuses the beam onto a target portion C of the substrate W. With the second positioner PW and the position sensor PS2 (for example, an interference measuring element, a linear encoder or a capacitive sensor), the substrate table WT can be accurately moved, for example, to position different target portions C to the radiation beam. In the path of B. Similarly, the first positioner PM and the other position sensor PS1 can be used to be aligned with respect to the path of the radiation beam B. The patterned element (eg, reticle) MA is positioned. Patterning elements (eg, reticle) MA and substrate W can be aligned using reticle alignment marks M1, M2 and substrate alignment marks P1, P2.

The depicted device can be used in at least one of the following modes:

1. In the step mode, when the entire pattern to be imparted to the radiation beam is projected onto the target portion C at a time, the support structure (eg, the mask table) MT and the substrate table WT are kept substantially stationary (ie, , single static exposure). Next, the substrate stage WT is displaced in the X and/or Y direction so that different target portions C can be exposed.

2. In the scan mode, when the pattern to be given to the radiation beam is projected onto the target portion C, the support structure (for example, the mask table) MT and the substrate table WT (ie, single dynamic exposure) are synchronously scanned. . The speed and direction of the substrate stage WT relative to the support structure (e.g., the mask stage) MT can be determined by the magnification (reduction ratio) and image reversal characteristics of the projection system PS.

3. In another mode, the support structure (eg, reticle stage) MT is held substantially stationary while the pattern imparted to the radiation beam is projected onto the target portion C, thereby holding the programmable patterning element, And moving or scanning the substrate table WT. In this mode, a pulsed radiation source is typically used and the programmable patterning elements are updated as needed between each movement of the substrate table WT or between successive radiation pulses during a scan. This mode of operation can be readily applied to matte lithography that utilizes programmable patterning elements, such as the programmable mirror array of the type mentioned above.

Combinations of the modes of use described above and/or variations or completely different modes of use may also be used.

Figure 2 shows the device 100 in more detail, which includes a source collector device SO, a lighting system IL, and a projection system PS. The source collector device SO is constructed and configured such that the vacuum environment can be maintained in the enclosure structure 220 of the source collector device SO. The EUV radiation emitting plasma 210 can be formed by a discharge generating plasma source. EUV radiation can be generated by a gas or vapor (e.g., Li vapor or Sn vapor), wherein the thermothermal plasma 210 is created to emit radiation in the EUV range of the electromagnetic spectrum. The thermothermal plasma 210 is created by, for example, causing discharge of at least a portion of the ionized plasma. For efficient generation of radiation, Li, Sn vapor or any other suitable gas or vapor fuel may be required, for example, at a partial pressure of 10 Pascals. In one embodiment, an excited tin (Sn) plasma is provided to produce EUV radiation.

The radiation emitted by the thermal plasma 210 is via an optional gas barrier or contaminant trap 230 positioned in or behind the opening in the source chamber 211 (also referred to as a contaminant barrier or foil trap in some cases). The source chamber 211 is transferred into the collector chamber 212. The contaminant trap 230 can include a channel structure. The pollution trap 230 can also include a gas barrier, or a combination of a gas barrier and a channel structure. As is known in the art, the contaminant trap or contaminant barrier 230 further indicated herein includes at least a channel structure.

The collector chamber 212 can include a radiation collector CO that can be a so-called grazing incidence collector. The radiation collector CO has an upstream radiation collector side 251 and a downstream radiation collector side 252. Radiation across the collector CO can be reflected from the grating spectral filter 240 to focus in the virtual source point IF. The virtual source point IF is generally referred to as an intermediate focus, and the source collector device is configured such that the intermediate focus IF is located at or near the opening 221 in the enclosure structure 220. Virtual source point IF is spoke An image of the emitted plasma 210.

Subsequently, the radiation traverses the illumination system IL, and the illumination system IL can include a faceted field mirror element 22 and a pupilized pupil mirror element 24, the faceted field mirror element 22 and the pupilized pupil mirror element 24 being configured The desired angular distribution of the radiation beam 21 at the patterned element MA and the desired uniformity of the radiation intensity at the patterned element MA are provided. After the reflection of the radiation beam 21 at the patterned element MA held by the support structure MT, a patterned beam 26 is then formed, and the patterned beam 26 is imaged by the projection system PS via the reflective devices 28, 30 to the wafer. The substrate W is held by the object table or the substrate table WT.

More devices than the devices shown can typically be present in the illumination optics unit IL and the projection system PS. Depending on the type of lithography device, a grating spectral filter 240 may be present as appropriate. Additionally, there may be more mirrors than the mirrors shown in the figures, for example, there may be one to six additional reflective devices in the projection system PS than the reflective devices shown in FIG.

As illustrated in Figure 2, the collector optics CO are depicted as nested collectors with grazing incidence reflectors 253, 254, and 255, just as an example of a collector (or collector mirror). The grazing incidence reflectors 253, 254, and 255 are disposed to be axially symmetric about the optical axis O, and collector optics CO of this type are desirably used in conjunction with a discharge generating plasma source (often referred to as a DPP source).

Alternatively, the source collector device SO can be a component of the LPP radiation system as shown in FIG. The laser LA is configured to deposit laser energy into a metal fuel such as tin (Sn) or lithium (Li) to create a highly ionized plasma 210 having an electron temperature of tens of electron volts. In this plasma to excite and then The high energy radiation generated during bonding is emitted from the plasma, collected by the near normal incidence collector optics CO, and focused onto the opening 221 in the enclosure structure 220.

Turning to Figure 4, this figure shows a schematic representation of a radiation source device for use in a method of one aspect of the invention. As with the embodiment shown in FIG. 3, the laser LA is configured to deposit laser energy into a metal fuel such as tin or lithium (in this case, tin) to create a highly ionized plasma 210. The high energy radiation generated from the plasma is collected by the collector optics CO and focused onto the opening 221 in the chamber or enclosure structure 220.

The chamber 220 is provided with a gas inlet pipe 40 and a gas outlet pipe 42. The gas inlet pipe 40 has a radical generator 41 located therein.

In use, in this example, a hydrogen and a boron hydride gas composed of hydrogen and boron hydride (in which the partial pressure of hydrogen is 100 Pascal and the partial pressure of boron hydride is 1 Pascal) flows into the chamber 220, and is passed through a radical generation. The device 41 enters the chamber 220 through the inlet tube 40. The gas passes over the collector mirror CO and exits the chamber 220 through the outlet tube 42. In this embodiment, the radical generator 41 is a microwave plasma generator, but other suitable plasma generators may alternatively be used. In addition to any free radicals generated by the free radical generator 41, hydrogen radicals may also be generated in the gas by the metal fuel plasma 210.

The presence of boron hydride at a partial pressure of 1 Pascal typically reduces the EUV intensity at 13.5 nm to about 3%, and thus, when the gas at the indicated partial pressure of hydrogen and boron hydride flows through the chamber 220, Efficiently operate the radiation source device. In order to maintain a clean internal surface without excessive accumulation of metal fuel deposits, it is not necessary to use the radiation source device to generate EUV The radical generator 41 is operated upon irradiation. This is because the free radicals generated by the metal fuel plasma 210 may be sufficient to provide cleaning. In the case where metal fuel deposits accumulate during operation of the radiation source device, the generation of interrupted radiation can be interrupted for a period of time having a higher hydrogen and boron hydride pressure to provide a greater purge rate, free of use in the absence of plasma 210 The base generator 41 generates hydrogen radicals from a gas. It will be apparent to those skilled in the art that various combinations of uses of fuel plasma 210 and free radical generator 41 can be used to use a low pressure gas during radiation generation and/or to use a particular pressure for cleaning. The gas is used to clean the device. Thus, for example, when the device is used to generate radiation, in addition to the generation of hydrogen radicals by the plasma 210, additional radicals may be simultaneously generated by the second radical generator 41.

The apparatus shown in Figure 4 is also suitable for use with a gas containing hydrogen in the absence of boron hydride.

The invention as set forth above may provide several advantageous features.

When the gas is excited by the first plasma generator to form hydrogen radicals during use, although the device is used to generate radiation, this situation provides the benefit of causing the deposited metal from the excited gas comprising hydrogen and boron hydride. The maintenance of the cleaned surface from the surface is performed simultaneously with the operation of the source device to produce radiation such as EUV radiation. In other words, the surface can be maintained in a clean state for a long period of time without disassembling the radiation source device for cleaning. In the case of this mode of operation, no special cleaning cycle is required, as this is due to the maintenance of the cleaning surface while generating radiation. The partial pressure of hydrogen and boron hydride is selected to provide good cleaning without causing strong radiation by absorption Excessive attenuation. This mode of operation of the method of the present invention is particularly useful for LPP radiation source devices in which gas is used in the chamber using hydrogen as the source of radiation, and thus, no method of operation of the device is required other than the addition of boron hydride to the gas stream. Specific changes.

Alternatively or additionally, the gas may be excited by a second radical generator that is separate from the first plasma generator to form hydrogen radicals. For example, a gas comprising hydrogen and boron hydride can be flowed through the chamber when the device is not used to generate radiation (eg, where the first plasma source is not turned on), and then, the device is used to generate radiation The gas containing hydrogen and boron hydride was previously replaced with an operating gas. For example, the operating gas may be, for example, an inert gas such as argon for the DPP radiation source, or may be hydrogen-free boron such as pure hydrogen for the LPP radiation source. This situation may be suitable for the case where the first plasma generator is operated in the presence of a gas containing hydrogen and boron hydride. For example, in the case of an LPP radiation source, the attenuation of EUV radiation resulting from the presence of hydrogenated boron during operation can be unacceptable. For example, in the case of a DPP radiation source, it may be undesirable to use hydrogen as a gas surrounding the plasma while generating radiation, as this may result in degradation of the electrode surface. In order to use the present invention to process a DPP radiation source device, it is appropriate to use the method of the present invention as a cleaning cycle in which an operating gas such as argon is first replaced with a gas comprising hydrogen/boron boron when the radiation is interrupted. This situation provides the benefit that the DPP radiation source can still be processed to remove metal deposits from the surface without disassembling the device and without exposing the interior surface to atmospheric pressure.

The gas flowing through the chamber can range from 10 Pascals to 500 Pascals Hydrogen is pressurized, such as from 50 Pascals to 200 Pascals, and comprises boron hydride from 0.1 Pascal to 5 Pascals, such as from 0.2 Pascal to 2 Pascal. By using these levels, proper removal of the deposited metal fuel can be possible without excessive attenuation of the radiation (especially EUV radiation) by the gas. Lower partial pressures provide insufficient cleaning, and higher partial pressures can result in excessive loss of radiation intensity in the EUV region of the spectrum. This situation is particularly undesirable when the radiation source device is used to generate EUV radiation to allow gas to flow through the chamber.

In this specification, a method of processing or operating a radiation source device, for example, for generating EUV radiation for component lithography, is disclosed. The method is for use with a radiation source device configured to hold a chamber for radiation-generated plasma, wherein the plasma is energized from the metal fuel by a first plasma generator when in use. The method includes flowing a gas comprising hydrogen and boron hydride through a chamber, wherein the gas in an excited state comprises hydrogen radicals. The presence of boron hydride and hydrogen radicals in the gas is effective to clean or reduce the accumulation of metal fuel deposits on the surface of the chamber or associated optics, particularly on the reflective surface of the radiation collector mirror. This method is particularly suitable for use with tin fuels.

The hydrogen radicals may be generated by the first plasma generator itself, or may involve the use of a second separation radical generator to excite the gas. The method can be used to reduce deposition when the radiation source device is used to generate radiation, or can be applied as a treatment for cleaning when interrupted radiation is generated.

It has been found that the addition of a small amount of boron hydride to the hydrogen gas can result in a metal fuel deposited on the surface within the radiation source device in the presence of hydrogen radicals generated by the radiation itself or by the separation free radical generator. Amazing improvement in cleaning. Without wishing to be bound by theory, it is believed that the presence of boron hydride in the gas will allow for the removal of metal fuel deposits in the presence of hydrogen radicals. Boron has only 3 electrons in its outer shell and thus forms a strong Lewis acid compound. Boron hydride as a dimer only exist B ₂ H _6, B ₂ H ₆ dimer is known to form a metal such as a tin hydride compound, e.g., H ₃ B-SnH _3. Due to the strong Lewis acid behavior of boron, it is expected that the addition of boron hydride to the hydrogen in the chamber in the presence of hydrogen radicals will then form a dimer comprising both boron and metal. Boron hydride is extremely volatile, so the co-dimer of boron hydride and metal should be more volatile than the metal hydride formed in the presence of hydrogen alone. Therefore, the addition of boron hydride to hydrogen can result in substantial and surprising improvements in cleaning performance.

An aspect of the invention as already mentioned above also provides a method of processing or operating a radiation source device, the device comprising a chamber configured to hold a plasma for radiation generation, the plasma being used by The first plasma generator is excited from a metal fuel, the method comprising flowing a gas comprising hydrogen through the chamber, wherein the gas system is excited by a second free radical generator to form hydrogen radicals. For this aspect of the invention, it is desirable, but not essential, to have boron hydride in the gas. The use of a separate second free radical generator allows for the creation of high levels of hydrogen radicals to provide surface cleaning so that effective cleaning can be achieved without the need to incorporate additional boron hydride.

Although reference may be made specifically to the use of lithography devices in IC fabrication herein, it should be understood that the lithographic devices described herein may have other applications, such as manufacturing integrated optical systems, for magnetic domain memory. Lead detection patterns, flat panel displays, liquid crystal displays (LCDs), thin film heads, etc. Wait. Those skilled in the art should understand that in the context of the content of such alternative applications, any use of the terms "wafer" or "die" herein is considered synonymous with the more general term "substrate" or "target portion". . The substrates referred to herein may be processed before or after exposure, for example, in a coating development system (typically applying a resist layer to the substrate and developing the exposed resist), metrology tools, and/or inspection tools. . Where applicable, the disclosure herein may be applied to such and other substrate processing tools. In addition, the substrate can be processed more than once, for example, to create a multi-layer IC, such that the term "substrate" as used herein may also refer to a substrate that already contains multiple processed layers.

Although the use of embodiments of the present invention in the context of the content of optical lithography may be specifically referenced above, it should be appreciated that the present invention can be used in other applications (eg, imprint lithography) and not when the context of the content allows Limited to optical lithography. In imprint lithography, the topography in the patterned element defines the pattern created on the substrate. The patterning element can be configured to be pressed into a resist layer that is supplied to the substrate where the resist is cured by application of electromagnetic radiation, heat, pressure, or a combination thereof. After the resist is cured, the patterned elements are removed from the resist to leave a pattern therein.

The term "lens", as the context of the context permits, may refer to any or a combination of various types of optical components, including refractive, reflective, magnetic, electromagnetic, and electrostatic optical components.

Although the specific embodiments of the invention have been described above, it is understood that the invention may be practiced otherwise than as described. For example, the radiation source device can be a DPP source, wherein the method of the invention is applied to a separate cleaning cycle when the source does not actively generate EUV radiation. the above The description is intended to be illustrative and not limiting. Therefore, it will be apparent to those skilled in the art that the present invention may be modified without departing from the scope of the appended claims.

The term "EUV radiation" can be considered to encompass a range from 5 nm to 20 nm (eg, in the range of 13 nm to 14 nm, for example, in the range of 5 nm to 10 nm, such as Electromagnetic radiation of a wavelength of 6.7 nm or 6.8 nm).

It will be understood that the use of the terms such as "preferred", "preferably" or "better" in this description may indirectly indicate that the features so described may be desirable, but may still be unnecessary and may be absent Embodiments of this feature are intended to be within the scope of the invention as defined in the appended claims. With regard to the scope of patent application, we hope that when words such as "one", "at least one" or "at least a portion" are used in front of a feature, there is no intention to limit the scope of the patent application to only one such feature, unless The scope of the patent application is specifically stated to the contrary. When the language "at least a portion" and/or "a portion" is used, the item may include a portion and/or the entire item, unless specifically stated to the contrary.

It should be understood that the [Embodiment] section, rather than the [Summary of the Invention] and the [Chinese Abstracts] section, are intended to explain the scope of the patent application. The invention and the [Chinese Abstract] section may explain one or more, but not all, of the exemplary embodiments of the invention as contemplated by the inventors of the present invention, and therefore, are not intended to limit the invention in any way. Additional patent application scope.

The present invention has been described above by means of functional building blocks that illustrate the implementation of the specified functions and relationships. For the convenience of description, this article has arbitrarily defined such The function builds the boundaries of the block. Alternate boundaries can be defined as long as the specified functions and the relationships of the functions are performed appropriately.

The foregoing description of the specific embodiments of the present invention will fully disclose the general nature of the invention, and the invention can be easily modified and/or modified for various applications by the knowledge of those skilled in the art without departing from the general inventive concept. Or adapting to these specific embodiments without undue experimentation. Therefore, the adaptations and modifications are intended to be within the meaning and scope of the equivalents of the disclosed embodiments. It is to be understood that the terms of the present invention are intended to be construed as a

The breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but only by the scope of the following claims and their equivalents.

21‧‧‧radiation beam

22‧‧‧琢面面镜镜元件

24‧‧‧Flat surfaced mirror components

26‧‧‧ patterned beam

28‧‧‧Reflective devices

30‧‧‧Reflective devices

40‧‧‧ gas inlet pipe

41‧‧‧Second free radical generator

42‧‧‧ gas outlet pipe

100‧‧‧ device

210‧‧‧Extreme ultraviolet (EUV) radiation emission plasma / very hot plasma / highly ionized plasma / metal fuel plasma

211‧‧‧ source chamber

212‧‧‧ Collector chamber

220‧‧‧Enclosed structure/chamber

221‧‧‧ openings

230‧‧‧ gas barrier/contaminant trap/contaminant barrier

240‧‧‧Grating spectral filter

251‧‧‧Upstream radiation collector side

252‧‧‧ downstream radiation collector side

253‧‧‧grazing incident reflector

254‧‧‧ grazing incident reflector

255‧‧‧grazing incident reflector

B‧‧‧radiation beam

C‧‧‧Target section

CO‧‧‧radiation collector/near normal incidence collector optics/collector mirror

IF‧‧‧virtual source/intermediate focus

IL‧‧‧Lighting System/Illuminator/Lighting Optics Unit

LA‧‧‧Laser

M1‧‧‧mask alignment mark

M2‧‧‧Photomask alignment mark

MA‧‧‧patterned components

MT‧‧‧Support structure

O‧‧‧ optical axis

P1‧‧‧ substrate alignment mark

P2‧‧‧ substrate alignment mark

PM‧‧‧First Positioner

PS‧‧‧Projection System

PS1‧‧‧ position sensor

PS2‧‧‧ position sensor

PW‧‧‧Second positioner

SO‧‧‧ source collector module / source collector device

W‧‧‧Substrate

WT‧‧‧Substrate/wafer stage

1 depicts a lithography apparatus in accordance with an embodiment of the present invention.

Figure 2 is a more detailed view of the device.

3 is a more detailed view of the source collector device of the apparatus of FIGS. 1 and 2.

4 depicts a schematic plan view of a radiation source device adapted for use in a method in accordance with an embodiment of the present invention.

40‧‧‧ gas inlet pipe

41‧‧‧Second free radical generator

42‧‧‧ gas outlet pipe

210‧‧‧Extreme ultraviolet (EUV) radiation emission plasma / very hot plasma / highly ionized plasma / metal fuel plasma

220‧‧‧Enclosed structure/chamber

221‧‧‧ openings

CO‧‧‧radiation collector/near normal incidence collector optics/collector mirror

IF‧‧‧virtual source/intermediate focus

LA‧‧‧Laser

O‧‧‧ optical axis

SO‧‧‧ source collector module / source collector device

Claims (15)

A method of processing or operating a radiation source device, the device comprising a chamber configured to hold one of the plasmas for radiation generation, wherein the plasma is used by a first plasma generator from a metal during use Excited by a fuel, the method includes flowing a gas comprising hydrogen and boron hydride through the chamber, wherein the gas in an excited state comprises hydrogen radicals. The method of claim 1, wherein the gas containing hydrogen radicals in an excited state during operation of the radiation source flows through the chamber. The method of claim 1 or 2, wherein the gas system is excited by the first plasma generator to form hydrogen radicals during use. The method of claim 3, wherein the radiation source device is a laser generating plasma device, wherein the first plasma generator comprises a laser beam directed to the metal fuel. The method of claim 1 or 2, wherein the gas system is excited by a second radical generator separated from the first plasma generator to form a hydrogen radical. The method of claim 5, wherein the second radical generator is a second plasma generator. The method of claim 5, wherein the second radical generator is selected from the group consisting of a thermal cracker, a microwave plasma generator, and an inductively coupled plasma generator. The method of claim 5, wherein the gas system is excited by the second radical generator to form hydrogen radicals before the gas enters the chamber. The method of claim 1 or 2, wherein the gas in an excited state flows through the chamber when the radiation source device is not used to generate radiation. The method of claim 1 or 2, wherein the radiation source device is a discharge generating plasma device, wherein the first plasma generator comprises a laser beam guided to the metal fuel to generate a metal fuel vapor, and A discharge pair electrode is provided for generating one of the plasmas for radiation generation by discharging through the metal fuel vapor. The method of claim 1 or 2, wherein the gas is directed to flow over a reflective surface of one of the radiation collectors of the chamber, or the gas flowing through the chamber comprises hydrogen from 10 Pascals to 500 Pascals and Boron hydride from 0.1 Pascal to 5 Pascal partial pressure. The method of claim 1 or 2, wherein the gas consists essentially of hydrogen and boron hydride, or the metal fuel is a tin fuel. A method of processing or operating a radiation source device, the device comprising a chamber configured to hold one of the plasmas for radiation generation, the plasma system being in use by a first plasma generator from a metal fuel While energizing, the method includes flowing a gas comprising hydrogen gas through the chamber, wherein the gas system is excited by a second free radical generator to form hydrogen radicals. A component manufacturing method comprising projecting a patterned radiation beam onto a substrate, wherein the radiation beam is generated using a radiation source device, the radiation source device comprising a plasma configured to hold for radiation generation. a chamber for generating radiation that is excited by a source of excitation radiation from a metal fuel during use, the method comprising flowing a gas comprising hydrogen and boron hydride through the chamber, wherein When the radiation is generated, the gas system is used for radiation production. The plasma is excited to generate hydrogen radicals. A lithography apparatus comprising: an illumination system configured to adjust a radiation beam; a support configured to support a patterned element, the patterned element being capable of traversing a cross section of the radiation beam The radiation beam imparts a pattern to form a patterned radiation beam; a substrate stage configured to hold a substrate; and a projection system configured to project the patterned radiation beam to a target of the substrate Partially; wherein the illumination system comprises a radiation source device, the radiation source device comprising a first plasma generator and a chamber configured to hold one of the plasmas for radiation generation, the plasma system being in use Excited by the first plasma generator from a metal fuel, the lithography apparatus further comprising means for flowing a gas comprising hydrogen gas through one of the chambers, and configured to excite the gas to flow through the A second radical generator of one of the hydrogen radicals is generated in the gas of the chamber.