Source: http://www.google.com/patents/US7609067?ie=ISO-8859-1
Timestamp: 2015-05-29 17:39:02
Document Index: 744782690

Matched Legal Cases: ['art 500', 'art 500', 'art 500', 'art 500', 'art 500', 'art 500']

Patent US7609067 - Electronic portion of an ion gauge with ion collectors bowed out of plane to ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsEmbodiments of the present invention pertain to an electronic portion of a MEMs ion gauge with ion collectors bowed out of plane to form a three dimensional arrangement and a method for forming an electronic portion of a MEMs ion gauge with ion collectors bowed out of plane to form a three dimensional...http://www.google.com/patents/US7609067?utm_source=gb-gplus-sharePatent US7609067 - Electronic portion of an ion gauge with ion collectors bowed out of plane to form a three dimensional arrangementAdvanced Patent SearchPublication numberUS7609067 B1Publication typeGrantApplication numberUS 11/269,960Publication dateOct 27, 2009Filing dateNov 9, 2005Priority dateNov 9, 2005Fee statusLapsedPublication number11269960, 269960, US 7609067 B1, US 7609067B1, US-B1-7609067, US7609067 B1, US7609067B1InventorsChien-Hua Chen, James McKinnellOriginal AssigneeHewlett-Packard Development Company, L.P.Export CitationBiBTeX, EndNote, RefManPatent Citations (5), Classifications (16), Legal Events (5) External Links: USPTO, USPTO Assignment, EspacenetElectronic portion of an ion gauge with ion collectors bowed out of plane to form a three dimensional arrangement
US 7609067 B1Abstract
Embodiments of the present invention pertain to an electronic portion of a MEMs ion gauge with ion collectors bowed out of plane to form a three dimensional arrangement and a method for forming an electronic portion of a MEMs ion gauge with ion collectors bowed out of plane to form a three dimensional arrangement. In one embodiment, an ion gauge substrate is formed. The electronic portion of the MEMs ion gauge is assembled by coupling a plurality of ion collectors with the ion gauge substrate, wherein the coupling of the plurality of ion collectors with the ion gauge substrate further comprises performing an operation that causes the plurality of ion collectors to be bowed out of plane to form a three dimensional arrangement.
Embodiments of the present invention relate to ion gauges. More specifically, embodiments of the present invention relate to ion gauges with ion collectors bowed out of plane to form a three dimensional arrangement.
Frequently, there is a need to measure the vacuum level of a package. For example, a MicroElectroMechanical System (MEM) is typically a very small device that can be used to sense pressure, temperature, chemical, vibration, light, among other things, in packaging devices (MEM's package). There is a need for maintaining a vacuum in MEMs packages. Ion gauges can be used, among other things, for measuring the vacuum level by measuring the ratio between an ion current and an electrical current, as will become more evident.
FIG. 2A depicts a top-down view of a conventional electronic portion of a MEMs ion gauge 100. FIG. 2B depicts a side view of a conventional electronic portion of a MEMs ion gauge 100. Referring to FIGS. 2A, 2B, the hot filaments 122 boil off electrons (e.g., “e−”), the positively charged bias grids 124 accelerate the electrons, and the negatively charged ion collectors 126 gather the positively charged ions (e.g., “ions+”). Referring to FIG. 2B, the ions are generated when the highly accelerated electrons collide with the residual gas molecules so that the ratio of ion current to the electron current at the bias grids 124 (e.g., lion Iion/Ielectron) is inversely proportional to the vacuum level. Therefore, the ion current can be expressed as in equation 1 depicted below:
Embodiments of the present invention pertain to an electronic portion of a MEMs ion gauge with ion collectors bowed out of plane to form a three dimensional arrangement and a method for forming an electronic portion of a MEMs ion gauge with ion collectors bowed out of plane to form a three dimensional arrangement. In one embodiment, an ion gauge substrate is formed. The electronic portion of the ion gauge is assembled by coupling a plurality of ion collectors with the ion gauge substrate, wherein the coupling of the plurality of ion collectors with the ion gauge substrate further comprises performing an operation that causes the plurality of ion collectors to be bowed out of plane to form a three dimensional arrangement.
Overview of an Electronic Portion of an Ion Gauge that has Ion Collectors Bowed Out of Plane to Form a Three Dimensional Arrangement
Referring to the conventional electronic portion of a MEMs ion gauge 100 depicted in FIGS. 1A-2B, the hot filaments 122, bias grids 124 and ion collectors 126, and connections to the bond pads 130 of a conventional electronic portion of a MEMs ion gauge 100 participate in collecting ions. Thus, they (e.g., hot filaments 122, bias grids, 124 and ion collectors 126, and connections to the bond pads 130) interfere with the accuracy of the conventional MEMs ion gauge 100 in measuring the level of vacuum. More specifically, the bias grids 124, ion collectors 126 and connections to bond pads 130 participate in collecting ions due to the bond pads 130 (FIG. 1A) being too close to the trench 110. For example, the bond pads 130 are adjacent to the trench 110 in the conventional electronic portion of a MEMs ion gauge 100. As a result, connections to the bond pads 130 and the bond pads 130 participate in collecting ions. The accuracy of measuring the vacuum level can be improved by moving the bond pads 130 further away from the trenches 110, according to one embodiment of the present invention as will be discussed further hereinafter.
An Electronic Portion of an Ion Gauge that has Ion Collectors Bowed Out of Plane to Form a Three Dimensional Arrangement
According to one embodiment of the present invention, FIG. 3A depicts a side view of the electronic portion of a MEMs ion gauge with hot filament bowed out of plane to form a three dimensional arrangement using thermal expansion and recrystallization, and FIG. 3B depicts a side view of the ion gauge depicted in FIG. 3A. According to another embodiment of the present invention, FIG. 3C depicts a side view of the electronic portion of the MEMs ion gauge that was formed using standard lithography techniques following formation using standard lithography techniques, if desired, a subset of the filaments may be bowed out of plane to form a three dimensional arrangement using thermal expansion and recrystallization. FIG. 3D depicts a side view of the electronic portion of the ion gauge depicted in FIG. 3C. The electronic portions of ion gauges 300A, 300B are MEMs type electronic portions of ion gauges, according to embodiments of the present invention.
The three dimensional arrangement formed by the hot filaments 322, bias grids 324, and ion collectors 326 that are bowed out of plane results in a “larger arrangement volume” of the hot filaments 322, the bias grids 324 and the ion collectors 326, according to embodiments of the present invention, than what is found in conventional electronic portions of ion gauges 100 (FIGS. 1A, 1B). For example, note that with the conventional electronic portion of an ion gauge 100 (FIGS. 1A, 1B) all of the hot filament 122, bias grids 124, and ion collectors 126 are in a single plane, whereas with the electronic portions of ion gauges 300A, 300B the hot filaments 322, bias grids 324, and ion collectors 326 are not arranged in a single plane (e.g., are out of plane and form a three dimensional arrangement) and therefore, cover a larger volume. A “larger arrangement volume” increases the probability of gas molecules colliding with ions. Therefore, the electronic portion of an ion gauge 300A, 300B, according to embodiments of the present invention, is more accurate in measuring vacuum level than a conventional electronic portion of an ion gauge 100.
As already stated, an electronic portion of an ion gauge 300A, 300B has an associated height 372, length 376, and width 374. According to one embodiment, the length 376 ranges from 1 millimeter (mm) to 20 mms, the width 374 of the trench 310 is approximately 0.5 mm, and the height 372 is approximately the height of a one-two semi-conductor wafers. Typically the height of a semi-conductor wafer is approximately 675 microns.
The bond rings 360 can be made out of Au88Ge12 (wt %) eutectic solder, Au80Sn20 (wt %), Au, Cu, Au10Sn90 (wt %), among other things, according to one embodiment
Hot Filaments, Bias Grids, and Ion Collectors that are Bowed Out of Plane to Form a Three Dimensional Arrangement
According to another embodiment, the hot filaments 322, bias grids 324, and/or ion collectors 326 are bowed out of plane to form a three dimensional arrangement. For example, the hot filaments 322, bias grids 324, and/or ion collectors 326 can be bowed out of plane to form a three dimensional arrangement using high temperature thermal cycles produced for example by passing an electrical current through the traces that form the hot filaments 322, bias grids 324, and/or ion collectors 326. FIG. 4A depicts a top down view of an electronic portion of a MEMs ion gauge with traces bowed out of plane to form a three dimensional arrangement and FIG. 4B depicts an cross section view of the electronic portion of an ion gauge depicted in FIG. 4A, according to one embodiment. For example, FIG. 4A depicts a top down view of an electronic portion of an ion gauge 300A, 300B with bowed tungsten traces A, B, C that has a side view A′-A′. FIG. 4B depicts the same electronic portion 300A, 300B from the cross section view A′-A′ with the traces A, B, C bowed downwards. The bias grids and ion collectors only need to be heated once, before a device that includes an electronic portion of a MEMs ion gauge is placed in operation, according to one embodiment. The hot filament is heated during operation, according to another embodiment.
The following is a more detailed description of how thermal cycles can be used for causing traces A, B, C to bend and controlling the bending process. For example, the traces A, B, C can be suspended over a trench 310 with their ends attached at each side of the trench 310 (refer to FIG. 4B). The slenderness ratio for these traces A, B, C with a rectangular profile is L/k−L(12)0.5/(2t) where L is the length 376 of a trace and t is the thinness of the trace. These traces A, B, C bend in towards the trench 310 or outwards from the trench 310 when, for example, the critical forces in Euler's column equation is exceeded, according to one embodiment. The critical force on the traces A, B, C is exceeded, for example, when a current is passed through the trace causing the temperature to rise which in turn generates a force on the column due to thermal expansion. Once a trace A, B, C bends, the degree of permanent bending when the trace is cooled can be controlled by the ultimate trace temperature and the time at which the temperature is reached. The temperature can be controlled at least in part by how much current is passed through a trace A, B, C. If the temperature is high enough and remains hot long enough for re-crystallization to take place, the trace A, B, C can take on a permanent “bow.”
A Method of Forming an Electronic Portion of an Ion Gauge with Ion Collectors that are Bowed Out of Plane
FIG. 5 depicts a flowchart 500 of a method for forming an electronic portion of a MEMs ion gauge that has ion collectors bowed out of plane to form a three dimensional arrangement, according to embodiments of the present invention. Although specific steps are disclosed in flowchart 500, such steps are exemplary. That is, embodiments of the present invention are well suited to performing various other steps or variations of the steps recited in flowchart 500. It is appreciated that the steps in flowchart 500 may be performed in an order different than presented, and that not all of the steps in flowchart 500 may be performed. For the purposes of illustration, the discussion of flowchart 500 shall refer to the structures depicted in FIGS. 6A-6E.
An electronic portion of an ion gauge 300A, 300B can be used to accurately measure the vacuum level due at least in part to ion collectors being bowed out of plane as described herein. An electronic portion of an ion gauge 300A, 300B can be used to accurately measure the vacuum level at least in part due to the bond pads 350 being 5000-6000 microns from the trench 310. Referring to FIGS. 3A and 3B, according to embodiments of the present invention, the arrangement of the hot filaments 322, ion collectors 326, and bias grids 324 cover a larger volume (referred to herein as “larger arrangement volume”) than the arrangement of hot filaments 122, ion collectors 326 and bias grids 124 in a convention electronic portion of an ion gauge 100 depicted in FIGS. 1A and 1B. An electronic portion of an ion gauge 300A, 300B can be used to accurately measure the vacuum level at least in part due to the “larger arrangement volume,” which increases the probability of gas molecules colliding with ions. Embodiments of the present invention provide for bowing the hot filaments 322, ion collectors 326, and/or bias grids 324 out of plane which can be used for providing the three dimensional arrangement with a “larger arrangement volume.” Embodiments of the present invention provide for controlling the extent and the direction in which the hot filaments 322, ion collectors 326, and/or bias grids 324 are bowed out of plane which can be used for providing the three dimensional arrangement with a “larger arrangement volume.”
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS4747311 *Mar 10, 1987May 31, 1988Seiko Instruments Inc.Gas pressure gageUS5493177 *Oct 26, 1993Feb 20, 1996The Regents Of The University Of CaliforniaSealed micromachined vacuum and gas filled devicesUS6051923 *Dec 2, 1997Apr 18, 2000Pong; Ta-ChingMiniature electron emitter and related vacuum electronic devicesUS6995502 *Feb 4, 2002Feb 7, 2006Innosys, Inc.Solid state vacuum devices and method for making the sameWO1995012211A1Oct 26, 1994May 4, 1995Univ CaliforniaSealed micromachined vacuum and gas filled devices* Cited by examinerClassifications U.S. Classification324/460, 250/427, 324/468, 250/489, 250/423.00R, 250/389, 250/336.1, 324/462, 324/464, 324/459, 315/111.91, 324/470, 250/424International ClassificationG01L21/30Cooperative ClassificationG01L21/32European ClassificationG01L21/32Legal EventsDateCodeEventDescriptionDec 17, 2013FPExpired due to failure to pay maintenance feeEffective date: 20131027Oct 27, 2013LAPSLapse for failure to pay maintenance feesJun 7, 2013REMIMaintenance fee reminder mailedSep 28, 2010CCCertificate of correctionNov 9, 2005ASAssignmentOwner name: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P., TEXASFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:CHEN, CHIEN-HUA;MCKINNELL, JAMES;REEL/FRAME:017214/0763Effective date: 20050714RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services