EP0943078A1 - Composant micromecanique d'enregistrement d'empreintes digitales - Google Patents

Composant micromecanique d'enregistrement d'empreintes digitales

Info

Publication number
EP0943078A1
EP0943078A1 EP97951795A EP97951795A EP0943078A1 EP 0943078 A1 EP0943078 A1 EP 0943078A1 EP 97951795 A EP97951795 A EP 97951795A EP 97951795 A EP97951795 A EP 97951795A EP 0943078 A1 EP0943078 A1 EP 0943078A1
Authority
EP
European Patent Office
Prior art keywords
membrane
individual sensors
membranes
grid
individual
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP97951795A
Other languages
German (de)
English (en)
Inventor
Thomas Scheiter
Christofer Hierold
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Original Assignee
Siemens AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Publication of EP0943078A1 publication Critical patent/EP0943078A1/fr
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/14—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators
    • G01L1/142—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators using capacitors
    • G01L1/148—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators using capacitors using semiconductive material, e.g. silicon
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/117—Identification of persons
    • A61B5/1171—Identification of persons based on the shapes or appearances of their bodies or parts thereof
    • A61B5/1172—Identification of persons based on the shapes or appearances of their bodies or parts thereof using fingerprinting
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/14—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators
    • G01L1/142—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators using capacitors
    • G01L1/146—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators using capacitors for measuring force distributions, e.g. using force arrays
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
    • G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
    • G06V40/12—Fingerprints or palmprints
    • G06V40/13—Sensors therefor
    • G06V40/1306—Sensors therefor non-optical, e.g. ultrasonic or capacitive sensing

Definitions

  • Fingerprinting is a common method of identifying people. There are different methods that use optical, acoustic or mechanical means.
  • EP 0 595 107 A3 describes a sensor arrangement for recording fingerprints, in which a raster-shaped arrangement of membranes as
  • Push button acts.
  • the membranes are each above a cavity and are each provided with a bump-like attachment. If the membranes are deformed according to the surface structure of the finger when a finger is placed on it, this different deformation of the individual membranes can be evaluated as a grid and provide an image of the finger structure.
  • the object of the present invention is to provide a simple to produce and reliable arrangement for taking fingerprints and an associated method for using this device.
  • a large number of individual sensors are arranged as a grid.
  • the width of the grid ie the distance of the individual sensors from one another, is chosen to be so small that a sufficiently precise reproduction of the surface of the finger is possible.
  • the individual sensors are designed as touch sensors with a micromechanical membrane. These membranes can be stamped to make contact with the surface of the fingers. The membranes are excited to vibrate, for which purpose a corresponding control circuit is used. The vibrations of the membranes are influenced in accordance with the contact pressure that is exerted on the stamp on the membrane. From the type of this influencing (eg change in the damping of the vibration) it can be determined whether there is a web or a groove in the finger structure at the point in question.
  • This fingerprint sensor can be manufactured as a micromechanical component in the context of a VLSI process, in particular a CMOS process, so that electronic components of the control and evaluation circuit can be integrated on the same chip.
  • FIGS. 1 and 2 A more detailed description of the fingerprint sensor according to the invention follows with the aid of FIGS. 1 and 2.
  • Figure 1 shows a grid-shaped arrangement of individual sensors in the cutout in supervision.
  • Figure 2 shows a cross section from the sensor in which a
  • FIG. 1 A grid-shaped arrangement of square individual sensors 31 is shown in FIG. In this case, the arrangement is selected as a double grille.
  • the membranes of the individual sensors can basically have any geometrical shapes. In addition to square membranes, rectangular, triangular or hexagonal membranes can also be used for the densest possible tiling of the surface provided for the measurement of the finger structure.
  • the area of the chip surface shown laterally in FIG. 1 is provided for an electronic circuit 32. Electronic components that serve to control the individual sensors can also be arranged in the area between the individual sensors 31 in order to reduce the transit times of the electrical signals.
  • FIG. 2 shows in cross section an individual sensor as a micromechanical component.
  • a substrate 1 including an uppermost semiconductor layer of a substrate, e.g. B.
  • the body silicon layer of an SOI substrate can be understood, there is a doped region 5 z. B. can be produced by diffusion of dopant into the semiconductor material.
  • a spacer layer 7 which, for. B. can be silicon dioxide, which in the case of a substrate 1 made of silicon is most easily produced by thermal local oxidation (LOCOS) of the silicon surface.
  • LOCOS thermal local oxidation
  • the membrane 2, under which a cavity 8 is etched out, is located on this spacer layer 7.
  • a stamp 10 is applied to the membrane 2 and does not cover the entire top of the membrane. This stamp 10 consists, for. B. from dielectric layers, such as in the context of a
  • this stamp 10 is present in a central region of the membrane and almost to the edge of the membrane.
  • the stamp which can be omitted in other embodiments, serves to establish a connection between the membrane and a flexible contact surface provided for the finger.
  • the sensors are preferably covered on the top with a passivation layer (e.g. with a gel).
  • the finger is therefore not directly on the stamps.
  • the surface of the membrane 2 is exposed along the edge, so that sufficient mobility of the membrane is ensured.
  • a pressure F is exerted on the upper side of the stamp 10 in the direction of the arrow shown, the membrane is therefore deformed downward towards the substrate.
  • a voltage can be applied between the membrane 2 and the doped region 5 via connection contacts 4, 6 on the electrically conductive membrane or an electrically conductive layer applied thereon and on the doped region 5 become.
  • a variation of this voltage leads to a change in the electrostatic attraction force exerted on the membrane and excites the membrane to vibrations which are damped by the force F.
  • This damping acts as a change in the impedance of the capacitor formed by the sensor.
  • This change in impedance or a change in the quality, ie the steepness of the resonance curve, of the vibratable membrane structure can be determined in the evaluation circuit. It is therefore possible to determine from the grid of individual sensors a contact pressure which differs locally when a finger is placed. In this way, the structure of the fingerprint can be determined.
  • the advantage of this arrangement is in particular that electronic components of the control and evaluation circuit can be integrated on the same chip together with the micromechanical components that form the individual sensors 31.
  • two MOSFETs 13, the z. B. can be complementary to each other. These transistors can be integrated with the micromechanical structures as part of a CMOS process.
  • a membrane 2 made of polysilicon can then, for. B. applied in the same process step in which the gate electrodes of the transistors are applied.
  • the top of the electronic components is preferably with a planarization layer 11, the z. B. BPSG
  • contacts are z. B. made by filling contact holes with contact metal.
  • a first metallization level which is structured to form conductor tracks and the like, is also shown in FIG. The top is covered with a passivation layer 12 z. B. covered from silicon nitride. Additional levels of milling can be provided which are separated from one another by intermediate dielectrics. separates and the interconnects are connected to each other with further vertical contacts.
  • the excitation frequency with which the membranes vibrate is preferably chosen to be less than or at most equal to the resonance frequency of the membranes. If the vibration of the membranes is influenced by the application of the finger, then characteristic quantities of the vibration of the membrane change, e.g. B. their amplitude, quality, phase or the like. In principle, it is possible to use any of these variables as a basis for the evaluation. Possibly. several of these characteristic quantities can also be used for the evaluation. By combining the data of the evaluation signal and the control circuit, an image of the surface structure of the finger can be generated. The vibrations of a single sensor on which one
  • Finger line is clearly distinguishable from the vibrations of the individual sensors, on which there is no finger line, which can therefore vibrate freely.
  • the local resolution of the fingerprint to be displayed is defined by a suitable placement of the individual sensors and the size of the grid size.
  • a control circuit can be provided which enables a separate control of each individual sensor or groups of individual sensors and the separate evaluation of the measurement signals supplied by the respective controlled individual sensors.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Power Engineering (AREA)
  • Pathology (AREA)
  • Medical Informatics (AREA)
  • Multimedia (AREA)
  • Biophysics (AREA)
  • Human Computer Interaction (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Theoretical Computer Science (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Image Input (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)

Abstract

Ce dispositif comprend des capteurs individuels constitués de capteurs de balayage pourvus d'une membrane micromécanique et agencés en une grille. Ces membranes sont pourvues de poinçons qui établissent le contact avec une surface de support. Un circuit de pilotage fait vibrer les membranes. Les vibrations des membranes sont modifiées en fonction de la pression exercée sur les poinçons situés sur la membrane. On peut déterminer à partir du type de ces modifications si aux endroits correspondants on trouve une crête ou un sillon de la structure digitale.
EP97951795A 1996-12-04 1997-11-20 Composant micromecanique d'enregistrement d'empreintes digitales Ceased EP0943078A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19650294 1996-12-04
DE19650294 1996-12-04
PCT/DE1997/002728 WO1998025115A1 (fr) 1996-12-04 1997-11-20 Composant micromecanique d'enregistrement d'empreintes digitales

Publications (1)

Publication Number Publication Date
EP0943078A1 true EP0943078A1 (fr) 1999-09-22

Family

ID=7813627

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97951795A Ceased EP0943078A1 (fr) 1996-12-04 1997-11-20 Composant micromecanique d'enregistrement d'empreintes digitales

Country Status (2)

Country Link
EP (1) EP0943078A1 (fr)
WO (1) WO1998025115A1 (fr)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4764996B2 (ja) * 2001-04-12 2011-09-07 富士電機株式会社 半導体物理量センサ装置
US7180798B2 (en) 2001-04-12 2007-02-20 Fuji Electric Co., Ltd. Semiconductor physical quantity sensing device
EP1707931B1 (fr) 2005-03-31 2013-03-27 STMicroelectronics Srl Dispositif d'entrée de données analogiques muni d'un capteur de pression microélectromécanique
EP1762925B1 (fr) 2005-09-09 2016-12-21 STMicroelectronics Srl Dispositif d'entrée analogique avec capteur de pression integré et appareil électronique équipé de ce dispositif d'entrée.
US10549982B2 (en) 2016-02-15 2020-02-04 Stmicroelectronics S.R.L. Pressure sensor encapsulated in elastomeric material, and system including the pressure sensor

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1094229A (fr) * 1976-11-08 1981-01-20 Henry Guckel Traduction non-disponible
DE4004179A1 (de) * 1990-02-12 1991-08-14 Fraunhofer Ges Forschung Integrierbarer, kapazitiver drucksensor und verfahren zum herstellen desselben
US5165289A (en) * 1990-07-10 1992-11-24 Johnson Service Company Resonant mechanical sensor
DE4236133C1 (de) * 1992-10-26 1994-03-10 Siemens Ag Sensoranordnung zur Erfassung von Fingerabdrücken und Verfahren zu deren Herstellung

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9825115A1 *

Also Published As

Publication number Publication date
WO1998025115A1 (fr) 1998-06-11

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