Abstract:
The present invention generally relates to a detection unit of a charged particle imaging system. More particularly, portion of the detection unit can move into or out of the detection system as imaging condition required. With the assistance of a Wein filter (also known as an E×B charged particle analyzer) and a movable detector design, the present invention provides a stereo imaging system that suitable for both low current, high resolution mode and high current, high throughput mode. Merely by way of example, the invention has been applied to a scanning electron beam inspection system. But it would be recognized that the invention could apply to other system using charged particle beam as an observation tool.
Abstract:
Novel proton exchange membrane fuel cells and direct methanol fuel cells with nanostructured components are configured with higher precious metal utilization rate at the electrodes, higher power density, and lower cost. To form a catalyst, platinum or platinum-ruthenium nanoparticles are deposited onto carbon-based materials, for example, single-walled, dual-walled, multi-walled and cup-stacked carbon nanotubes. The deposition process includes an ethylene glycol reduction method. Aligned arrays of these carbon nanomaterials are prepared by filtering the nanomaterials with ethanol. A membrane electrode assembly is formed by sandwiching the catalyst between a proton exchange membrane and a diffusion layer that form a first electrode. The second electrode may be formed using a conventional catalyst. The several layers of the MEA are hot pressed to form an integrated unit. Proton exchange membrane fuel cells and direct methanol fuel cells are developed by stacking the membrane electrode assemblies in a conventional manner.
Abstract:
An apparatus basically uses a simple and compact multi-axis magnetic lens to focus each of a plurality of charged particle beams on sample surface at the same time. In each sub-lens module of the multi-axis magnetic lens, two magnetic rings are respectively inserted into upper and lower holes with non-magnetic radial gap. Each gap size is small enough to keep a sufficient magnetic coupling and large enough to get a sufficient axial symmetry of magnetic scale potential distribution in the space near to its optical axis. This method eliminates the non-axisymmetric transverse field in each sub-lens and the round lens field difference among all sub-lenses at the same time; both exist inherently in a conventional multi-axis magnetic lens. In the apparatus, some additional magnetic shielding measures such as magnetic shielding tubes, plates and house are used to eliminate the non-axisymmetric transverse field on the charged particle path from each charged particle source to the entrance of each sub-lens and from the exit of each sub-lens to the sample surface.
Abstract:
An apparatus basically uses a simple and compact multi-axis magnetic lens to focus each of a plurality of charged particle beams on sample surface at the same time. In each sub-lens module of the multi-axis magnetic lens, two magnetic rings are respectively inserted into upper and lower holes with non-magnetic radial gap. Each gap size is small enough to keep a sufficient magnetic coupling and large enough to get a sufficient axial symmetry of magnetic scale potential distribution in the space near to its optical axis. This method eliminates the non-axisymmetric transverse field in each sub-lens and the round lens field difference among all sub-lenses at the same time; both exist inherently in a conventional multi-axis magnetic lens. In the apparatus, some additional magnetic shielding measures such as magnetic shielding tubes, plates and house are used to eliminate the non-axisymmetric transverse field on the charged particle path from each charged particle source to the entrance of each sub-lens and from the exit of each sub-lens to the sample surface.
Abstract:
The present invention relates to an operation stage of a charged particle beam apparatus which is employed in a scanning electron microscope for substrate (wafer) edge and backside defect inspection or defect review. However, it would be recognized that the invention has a much broader range of applicability. A system and method in accordance with the present invention provides an operation stage for substrate edge inspection or review. The inspection region includes top near edge, to bevel, apex, and bottom bevel. The operation stage includes a supporting stand, a z-stage, an X-Y stage, an electrostatic chuck, a pendulum stage and a rotation track. The pendulum stage mount with the electrostatic chuck has the ability to swing from 0° to 180° while performing substrate top bevel, apex and bottom bevel inspection or review. In order to keep the substrate in focus and avoid a large position shift during altering the substrate observation angle by rotation the pendulum stage, one embodiment of the present invention discloses a method such that the rotation axis of the pendulum stage consist of the tangent of upper edge of the substrate to be inspected. The electrostatic chuck of the present invention has a diameter smaller than which of the substrate to be inspected. During the inspection process the substrate on the electrostatic chuck may be rotated about the central axis on the electrostatic chuck to a desired position, this design insures all position on the bevel and apex are able to be inspected.
Abstract:
System and method for charged particle beam. According an embodiment, the present invention provides a charged particle beam apparatus. The apparatus includes a charged particle source for generating a primary charged particle beam. The apparatus also includes at least one condenser lens for pre-focusing the primary charge particle beam. Furthermore, the apparatus includes a compound objective lens for forming the magnetic field and the electrostatic field to focus the primary charged particle beam onto a specimen in the charged particle beam path. The specimen includes a specimen surface. The compound objective lens includes a conical magnetic lens, an immersion magnetic lens, and an electrostatic lens, the conical magnetic lens including an upper pole piece, a shared pole piece being electrically insulated from the upper pole piece, and an excitation coil.
Abstract:
Electrocatalyst durability has been recently recognized as one of the most important issues that have to be addressed before the commercialization of the proton exchange membrane fuel cells (PEMFCs). The present invention is directed to a new class of cathode catalysts based on supportless platinum nanotubes (PtNTs) and platinum alloy nanotubes, for example, platinum-palladium nanotubes (PtPdNTs), that have remarkable durability and high catalytic activity. Due to their unique combination of dimensions at multiple length scales, the platinum nanotubes of the present invention can provide high platinum surface area due to their nanometer-sized wall thickness, and have the potential to eliminate or alleviate most of the degradation pathways of the commercial carbon supported platinum catalyst (Pt/C) and unsupported platinum-black (PtB) as a result of their micrometer-sized length. The platinum nanotube catalysts of the present invention asymptotically approach a maximum of about twenty percent platinum surface area loss in durability test, while the commercial PtB and Pt/C catalysts lose about fifty-one percent and ninety percent of their initial surface area, respectively. Moreover, the PtNT and PtPdNT catalysts of the present invention show higher mass activity and much higher specific activity than commercial Pt/C and PtB catalysts.
Abstract:
A method for in-line monitoring of via/contact etching process based on a test structure is described. The test structure is comprised of via/contact holes of different sizes and densities in a layout such that, for a certain process, the microloading or RIE lag induced non-uniform etch rate produce under-etch in some regions and over-etch in others. A scanning electron microscope is used to distinguish these etching differences in voltage contrast images. Image processing and simple calibration convert these voltage contrast images into a “fingerprint” image characterizing the etching process in terms of thickness over-etched or under-etched. Tolerance of shifting or deformation of this image can be set for validating the process uniformity. This image can also be used as a measure to monitor long-term process parameter shifting, as well as wafer-to-wafer or lot-to-lot variations. Advanced process control (APC) can be performed in-line with the guidance of this image so that potential electrical defects are avoided and process yield ramp accelerated.
Abstract:
The present invention provides an electrode assembly comprising two or more electrodes arranged around a primary axis forming a non-cylindrical channel space. General electronic apparatus/device, particularly apparatus of charged-particle beam such as electron microscope, may use the electrode assembly to create an optimized pattern of electrical field within non-cylindrical channel space. When the electrode assembly is used as a beam deflector in a magnetic objective lens, the electrical field within the central channel space can be co-optimized with the magnetic field for reducing aberration(s) such as distortion, field curvature, astigmatism, and chromatic aberration, after the beam passes through the central channel space.
Abstract:
The present invention provides an apparatus of charged-particle beam such as an electron microscope including a specimen table that can slide on a planar surface around the lower pole piece of the objective lens. The specimen table is confined in a specimen stage having one elastic protrusion and one or more elastic force receiving parts (e.g three permanent protrusions) that contact and press the table. When the specimen is under microscopic examination, disturbing vibration cannot generate a force sufficient to overcome the limiting friction between the specimen table and the planar surface of the objective lens. The invention exhibits numerous technical merits such as minimal or zero vibration noise, and improved image quality, among others.