Abstract: A method and apparatus for removal of volatile contaminants from substrate surfaces before the substrate enters a process chamber. Substrate cleaning is achieved by irradiating the substrate with a low-energy electron beam. The interaction of the electrons in the beam with the contaminants present on the surface of the substrate causes evaporation of low vapor pressure species which can be deposited on the surface. A cryoshield pumps the evaporated species. After evaporation and pumping, the substrate passes through a glow discharge chamber wherein the negative surface charge created by the electron beam is neutralized using positive ions. The inventive apparatus can be configured so that no separate vacuum chamber is needed to prepare the substrate.

Abstract: A compact detector for secondary and backscattered electrons in a scanning electron beam system includes a microchannel plate detector and a solid state detector connected in a tandem manner. The detector offers large bandwidth and high dynamic range. The detector can be used for article inspection, lithography, metrology, and other related applications. The compactness of the detector makes it ideally suited for utilization in a miniature electron beam column, such as a microcolumn.

Abstract: A method and apparatus for removal of volatile contaminants from substrate surfaces before the substrate enters a process chamber. Substrate cleaning is achieved by irradiating the substrate with a low-energy electron beam. The interaction of the electrons in the beam with the contaminants present on the surface of the substrate causes evaporation of low vapor pressure species which can be deposited on the surface. A cryoshield pumps the evaporated species. After evaporation and pumping, the substrate passes through a glow discharge chamber wherein the negative surface charge created by the electron beam is neutralized using positive ions. The inventive apparatus can be configured so that no separate vacuum chamber is needed to prepare the substrate.

Abstract: In scanning lithography as used in the semiconductor industry, systematic variations in critical dimension feature size which depend on the substrate coordinates are compensated for in a lithography tool. This is done by determining (experimentally or theoretically) low frequency variations in the critical dimensions on the target caused by imperfections in the lithography tool and/or the resist and/or the process steps. These low frequency spatial errors are compensated for, after the primary scanning exposure using the original pattern data, by a secondary scanning exposure of the target using a weaker intensity and relatively larger diameter exposure beam. The secondary exposure is also carried out at a larger address size (address grid) than is the primary exposure so it is relatively fast in terms of throughput.

Abstract: A shield assembly for reducing electron fogging effects in electron beam lithography. This shield, located between an electron beam column final aperture and the beam target, is of multiple vanes with sharp edges pointing towards the electron beam incident point on the target; the vanes are conically shaped and concentric around the electron beam path, which travels through the center of the assembly. Additionally, the sharp edges are such that they present oblique surfaces at the ends of the vanes angled between 10° and 20° relative to the outer vane surface and these oblique surfaces face towards the electron beam path. Furthermore, the shield assembly may also have the vanes angled towards the beam incident point such that the vertex of the conical vane assembly is coincident with the beam incident point.

Abstract: A preload hydrostatic bearing includes a pad, a diaphragm and an adjustable member. The pad has a bearing structure, an inlet manifold, and a plurality of orifices. The orifices direct a fluid, such as air, from the inlet manifold toward the bearing surface. The diaphragm is mounted on the pad, and the adjustable member, which extends in an axial direction, is coupled proximate one end to a center portion of the diaphragm. The diaphragm transfers a preload in the axial direction to the adjustable member. This preload hydrostatic bearing has a high repeatability of performance, because a single diaphragm replaces prior art mechanical coupling devices, such as ball bearings, conical seats and spring washers, which undesirably are sources of friction and hysteresis.

Abstract: A vacuum seal facilitates the production of a vacuum with a localized region on the surface of a substrate, such as a semiconductor wafer or reticle, which is subject to electron beam lithography. The vacuum seal permits vacuum processing in a localized region while allowing the remainder of the substrate and its supporting stage to be outside the vacuum. In addition to conventional concentric differential pumping of vacuum zones to provide adequate vacuum, additional differential pumping is provided in the vertical direction where a lower vacuum level is maintained immediately above the substrate. Also, an isolation valve is provided between the high vacuum of the electron beam column and the lesser vacuum immediately above substrate. This valve allows isolation of the high vacuum surrounding the beam during times when the gap between an edge of the substrate and its coplanar carrier surface are directly under the vacuum seal. This protects the high vacuum during substrate loading and unloading.

Abstract: A method and an accompanied apparatus for aligning an electron emitter with an extractor hole of a microcolumn. Four V-grooves, defined together with the window for forming the membrane and having bottoms situated on two axis are microfabricated on a chip. The axis intersect at a right angle and defines a center point for the extractor hole. The V-grooves are then used as references to align the electron emitter with the extractor hole, one axis at a time. The emitter is precisely aligned to the extractor hole because the extractor hole was formed with reference to the V-grooves. The thickness of the chip is used as the spacing reference between the emitter and the extractor.

Abstract: An acousto-optic modulator for use with a multi-channel laser beam system, for instance, is of conventional structure except that two different RF (radio frequency) signals drive the modulator. These signals each produce at least one output beam as diffracted by the modulator body. These two beams are angularly and spatially separated. One of the sets of beams is incident upon a beam stop, and therefore is not used for writing. Only the other set of beams, driven by the other of the frequencies, performs the actual writing. The optical stop in addition to blocking one of the sets of diffracted beams also blocks the transmission of the zero order (undiffracted) beam. The sum of the load power of the signals at the two frequencies is kept approximately constant, thereby maintaining a constant thermal condition within the modulator.

Abstract: A field emission source produces a charged particle beam that can be electrostatically aligned with the optical axis. Quadrupole (or higher multipole) centering electrodes approximately centered on the optical axis are placed between the emitter and the extraction electrode. By applying centering potentials of equal amplitude and opposite polarity on opposing elements of the centering electrodes, an electrostatic deflection field is created near the optical axis. The electrostatic deflection field aligns the charged particle beam with the optical axis thereby obviating the need to mechanically align the emitter with the optical axis. A second set of centering electrodes may be used to deflect the charged particle beam back and to ensure that the charged particle beam is parallel with the optical axis. Further, the extraction electrode may be split into a quadrupole arrangement with the extraction and centering potentials superimposed.

Abstract: A method and the associated apparatus for alignment and assembly of microlenses and microcolumns in which aligning structures such as rigid fibers are used to precisely align multiple microlens components. Alignment openings are formed in the microlens components and standard optical fibers are threaded through the openings in each microlens component as they are stacked. The fibers provide sufficient stiffness and stability to the structure to precisely align the apertures of the microlens components and thereby allow for increased assembly efficiency over traditional microlens and microcolumn bonding techniques.

Abstract: A movable stage assembly suitable for use in a vacuum has three circular stages rotating independently of one another. The stage assembly includes a base and a large rotatable circular table mounted on the base. This large table has a second smaller circular table which is eccentrically mounted within the first large table and rotates independently. This second table also has a smaller third circular table eccentrically mounted on it and independently rotatable within the second table. All the rotatable tables utilize ferrofluidic seals to prevent air within the air bearings from leaking into the vacuum chamber and are driven by motors mounted beneath the tables.

Abstract: A hybrid exposure strategy for pattern generation uses wide field raster scan deflection and a uniformly moving stage to expose long stripes. Periodic analog wide field magnetic scan is augmented by a high speed electrostatic retrograde scan to keep the beam essentially stationary during exposure of rectangular flash fields and/or Gaussian beams. In this manner a staircase deflection trajectory is created for the beam. The position and dose data for each flash is derived from a rasterized data format using a decoder device.

Abstract: A precision printing system uses multiple scan beams that an acousto-optic modulator (AOM) separately modulates. An array of optical elements such as dove prisms separately rotates each of the beams about a central ray of the beam to eliminate blurred edges, skew, and variations in line thickness caused by the direction of propagation of acoustic waves in the AOM being at an angle to a scan direction. In particular, the amount of rotation is selected so that in the final image the direction in which illumination progresses across a cross-section of a beam is in a direction opposite the scan direction. A method of making the array includes attaching rods to a flat, grinding or polishing the combination of the rods and flat to form three planar regions that correspond to facets on prisms. Removing the rods/prisms from the flat. Using photolithography and etching to form grooves in a substrate, and a mounting the rods/prisms in the grooves on the substrate.

Abstract: An electron beam column (or other charged particle beam column) for lithography which exposes a surface to variable shapes in a raster scan. The beam column includes an electron (or ion) source that generates a charged particle beam, a transfer lens, an upper aperture, an upper deflector, a lower aperture, a lower deflector, magnetic deflection coils, and a beam objective lens. The beam is first shaped as a square in cross section by the upper aperture. The upper deflector changes the direction of the square shaped beam to pass through a specific portion of an opening defined in the lower aperture to shape the beam as desired. The lower aperture defines either a cross shaped opening or four L-shaped openings arranged as corners of a square. The combination of upper and lower apertures enable definition of exterior and interior corners as well as horizontal and vertical edges of a pattern, so that only one flash need be exposed in any one location on the surface.

Abstract: A converter for lithography which generates signals that control a shaping of an electron (or other energy) beam and which includes a translator that translates shape data into shape and position signals, and translates duration information into a duration signal. The converter also includes a retrograde scan circuit coupled to the translator that provides a retrograde signal that adjusts the position signal to offset a raster scan movement of the beam. The shape signals control the shaping of the beam, the position signal specifies a position of the beam for writing the shape on a substrate, and the duration signal specifies a duration of exposure of the beam on the substrate.

Abstract: An optical mask for high resolution optical lithography using short wavelength light, e.g., 157 nm, uses membranes of a material that is transparent to the desired wavelength. The thin membranes are held under tensile stress by a supporting structure, such as a silicon wafer. Because the membranes are thin, the heating of the membrane material during generation of the overlying lithographic patterns is reduced. This is particularly advantageous when a material such as calcium fluoride is used as the transparent medium of the mask because calcium fluoride has a high thermal expansion coefficient. Thus, the membrane will suffer little distortion during the production of the mask. The lithographic pattern is produced using a thin layer of a absorptive material, such as palladium. Because both the absorptive material and the membrane are thin, there is little back scattering during the generation of the lithographic pattern by e-beam writing, and consequently, no proximity correction is necessary.

Abstract: An electron gun assembly which integrates electronics required to power the electron gun and the electron gun itself in one module in a high voltage operating environment. The assembly has four major sections: interface cables; electronic circuits (active and high voltage); the electron emitter; and a mechanical enclosure for the assembly. The electronics portion of the assembly has two distinct sections: an active electronics section (which contains digital to analog converters, interface to a control computer, and analog outputs terminals to control the high voltage electronics) and a high voltage electronics section (which contains high-voltage multiplying circuits and feedback and filtering elements). These two sections are electrically connected and are present within an internal box at one end of the assembly, or alternately, the high voltage electronics section is disposed below the active electronics section and outside the internal box.

Abstract: A linear array of equal intensity optical beams is transformed into a rectangular array of equal intensity optical beams, while the intensity of each beam is kept nearly constant. The transformation is performed using an optical element which has two coatings on the front surface and a reflective coating on the opposing back surface. The front surface is partially coated with a reflective coating and partially coated with an anti-reflective coating. The beams are incident upon the front surface, with some of the beams incident on each of the two different coatings on the front surface. The beams incident on the front surface are specularly reflected. The remaining beams are transmitted through the optical element to the back surface, reflected from the back surface, and transmitted back up through the optical element and exit from the front surface. The exiting beams are thus shifted laterally and transversely to define the desired rectangular array.

Abstract: A photocathode having a gate electrode so that modulation of the resulting electron beam is accomplished independently of the laser beam. The photocathode includes a transparent substrate, a photoemitter, and an electrically separate gate electrode surrounding an emission region of the photoemitter. The electron beam emission from the emission region is modulated by voltages supplied to the gate electrode. In addition, the gate electrode may have multiple segments that are capable of shaping the electron beam in response to voltages supplied individually to each of the multiple segments.