Patents by Inventor Tai-Hon P Chang
Tai-Hon P Chang has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
-
Patent number: 6555829Abstract: Disclosed is a positioning stage for precisely positioning an object within a limited range of travel (e.g. 100 &mgr;m). By way of example, the stage can be used to position an electron source such as a field emitter in an electron beam microcolumn. The stage includes a block which defines a channel to allow flexure along a first axis. The block also defines another channel to allow flexure along a second axis perpendicular to the first axis. Using actuators in the channels to flex a portion of the block, the object supported by the block can be precisely positioned to a desired location in a horizontal plane defined by the first and second axes.Type: GrantFiled: January 10, 2000Date of Patent: April 29, 2003Assignee: Applied Materials, Inc.Inventors: James P. Spallas, Lawrence P. Muray, David Trost, Ho-Seob Kim, Tai-Hon P. Chang
-
Patent number: 6429443Abstract: Multiple beam electron beam lithography uses an array of vertical cavity surface emitting lasers (VCSELS) to generate laser beams, which are then converted to electron beams using a photocathode. The electron beams are scanned across a semiconductor substrate or lithography mask to imprint a pattern thereon. The use of VCSELs simplifies the design of the electron beam column and improves the throughput and writing resolution of the lithography system.Type: GrantFiled: June 6, 2000Date of Patent: August 6, 2002Assignee: Applied Materials, Inc.Inventors: Marian Mankos, Steven T Coyle, Andres Fernandez, Tai-Hon P Chang
-
Patent number: 6288401Abstract: 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.Type: GrantFiled: July 30, 1999Date of Patent: September 11, 2001Assignee: Etec Systems, Inc.Inventors: Tai-Hon P Chang, Marian Mankos, Lawrence P Muray, Ho-Seob Kim, Kim Y Lee
-
Patent number: 6023060Abstract: A charged particle-beam microcolumn, which for example may be used for charged particle microscopy, with a T-shape configuration has a relatively narrow base structure supporting the beam forming charged particle optical column. The narrow base structure permits the T-shaped microcolumn and sample to be positioned at an angle other than normal with respect to each other, which allows generation of three-dimensional-like images of the sample surface. Thus, the incidence angle of the charged particle beam generated by the T-shaped microcolumn may be varied while a short working distance is maintained. A conventional secondary/backscattered charged particle detector may be used because the reflected angle of the charged particles allows a charged particle detector to be separated from the T-shaped microcolumn. Further, the small size of the T-shaped microcolumn permits observation of different parts of a large stationary sample by moving the T-shaped microcolumn with respect to the sample.Type: GrantFiled: March 3, 1998Date of Patent: February 8, 2000Assignee: Etec Systems, Inc.Inventors: Tai-Hon P. Chang, Ho-Seob Kim
-
Patent number: 6011269Abstract: A shaped electron beam column focuses electrons from an electron source to produce a shadow image of a shaped aperture on a writing plane. The shadow image of the shaped aperture is the defocused image of a shape aperture. This defocused shadow image is in the the object plane of the shaped electron beam column. The shadow image in the writing plane is defocused because an electron beam lens produces a focused image of the electron source off the writing plane. The size of the shadow image on the writing plane may be altered by adjusting the electron beam lens to change the distance between the electron source image and the writing plane, i.e., defocus. Thus, a relatively large shaped aperture may be used in comparison to shaped apertures used in conventional electron beam columns. Further, only a small total linear demagnification may be used, which permits the length of the shaped electron beam column to be decreased.Type: GrantFiled: April 10, 1998Date of Patent: January 4, 2000Assignee: Etec Systems, Inc.Inventors: Lee H. Veneklasen, Tai-Hon P. Chang, Marian Mankos
-
Patent number: 5155412Abstract: The present invention is directed to a method for selectively scaling the dimensions of a field emission electron gun. The electron gun includes a field emission tip followed by a dual electrode immersion lens. The lens consists of two planar electrodes separated by a dielectric layer. A well defined circular hole is present at the center of each electrode and the dielectric layer. A high scaling factor is applied to the region consisting of the first electrode and the emission tip, reducing the first electrode thickness and bore diameter and the distance between the tip and first electrode to the micrometer range. A weaker scaling factor is applied to the bore diameter of the second electrode and the spacing between the electrodes such that the second electrode bore diameter and distance between the electrodes are approximately equal and are greater than the first electrode thickness and bore diameter and the distance between the tip and first electrode.Type: GrantFiled: May 28, 1991Date of Patent: October 13, 1992Assignee: International Business Machines CorporationInventors: Tai-Hon P. Chang, Dieter P. Kern, Lawrence P. Muray
-
Patent number: 5122663Abstract: An electron beam imaging system is described wherein a sharp-tip electron source is biased to produce an electron flow and a conductive target is placed in the path of the electron flow. A planar, electrostatic lens is positioned in the electron flow path and between the electron source and target. The lens includes an aperture; at least a first conductive plane that is biased less negative than the electron source; and one or more conductive planes separated by dielectric layers. A secondary electron detector is formed on the surface of the electrostatic lens that is closest to the conductive target, whereby the lens may be positioned close to the target and still not obstruct secondary electrons emitted from the target from impinging on the secondary electron detector.Type: GrantFiled: July 24, 1991Date of Patent: June 16, 1992Assignee: International Business Machine CorporationInventors: Tai-Hon P. Chang, Harry J. Mamin, Daniel Rugar
-
Patent number: 4621232Abstract: Apparatus and methods are disclosed for inspecting unsintered single or multiple layer ceramic specimens containing or carrying metal paste patterns of the type commonly used to ultimately form laminated multilayer ceramic (MLC) carriers for large scale integrated (LSI) chips. A relatively large surface area of an unsintered ceramic specimen (large in comparison with the minimum feature size of the paste patterns) is temporarily electrically contacted with a conforming electrode. The conforming electrode makes non-damaging electrical contact to any metallic paste exposed at the contacted area. Electric charge is either collected or delivered by this electrode, depending upon the mode of operation.Type: GrantFiled: May 15, 1984Date of Patent: November 4, 1986Assignee: International Business Machines CorporationInventors: Tai-Hon P. Chang, Philip J. Coane, Fritz-Jurgen Hohn, Walter W. Molzen, Jr., Arthur R. Zingher
-
Patent number: 4477729Abstract: A large lithographic pattern is written as quickly as possible by writing successive subpatterns in a vector scan mode of operation without any interruption between successive subpatterns. This is made possible by arranging the subpatterns so that they are adjacent to each other and are preferably overlapping and by gradually moving the workpiece with respect to the writing field so as to always keep the subpattern being written within the writing field of the beam. The speed and direction of the workpiece movement (relative to the writing field) is not predetermined for all patterns but is controlled instead by the pattern being written. A sparsely written pattern or portion of a pattern is accompanied by a more rapid table movement than what accompanies a densely written pattern or portion of a pattern. This is made possible by embedding pattern determined workpiece movement commands within the pattern defining data.Type: GrantFiled: October 1, 1982Date of Patent: October 16, 1984Assignee: International Business Machines CorporationInventors: Tai-Hon P. Chang, Alan D. Wilson
-
Patent number: 4426583Abstract: The electron potential of an electron beam is switched between different values without moving the focal plane by effectively changing the axial position of the electron source at the same time that the electron potential is changed. The effective change in axial position of the electron source exactly compensates for the altered effectiveness which magnetic lenses have upon an electron beam of altered electron potential such that the final focal plane remains at the same position without adjusting the field strength of any magnetic lens.Type: GrantFiled: May 10, 1982Date of Patent: January 17, 1984Assignee: International Business Machines CorporationInventors: Tai-Hon P. Chang, Phillip J. Coane, Fritz-Jurgen Hohn, Dieter P. Kern
-
Patent number: 4165395Abstract: A high aspect ratio structure (with a large height-to-linewidth ratio) is formed on a substrate by means of two resist layers with different kinds of radiation to which they are sensitive, respectively, with an actinic radiation sensitive resist below and an electron sensitive resist above. In addition, a metallic film is shaped by means of exposure of the upper layer of resist to form a metallic mask through which the lower layer of resist is exposed. Exposure may be performed by a "subtractive" technique or an "additive" technique. In the case of the subtractive technique, the substrate is coated by a first actinic resist above which are deposited first a metallic film and then a top layer of electron resist. The top resist layer is exposed and developed and the metal layer is etched so the lower resist can be exposed and developed with the pattern formed in the metal, with the pattern shape originally exposed in the top layer of resist extending down to the substrate.Type: GrantFiled: June 30, 1977Date of Patent: August 21, 1979Assignee: International Business Machines CorporationInventor: Tai Hon P. Chang