International
`Congress On
`Transportation
`Electronics
`
`- PROCEEDINGS -
`
`IEEE catalog number: 88CH2533-8
`
`

`

`lerary of Congress Catalog Card Number: 87-83470
`
`Page 000002
`
`

`

`WELCOME TO CONVERGENCE '88
`
`
`
`On behalf of the Executive Committee and all the sub—committees,
`
`welcome to the l988 international Congress on
`Transportation Electronics.
`
`This year’s conference brings researchers, engineers and executives from
`all over the world together to explore system integration as the key
`to reliability, flexibility and cost effectiveness for vehicle manufacturers worldwide. The
`vehicle of the future depends on systems integration in ways we are just
`beginning to understand.
`
`By the turn of the century, electronics will be the second largest industry in
`the world, second only to agriculture. The automotive electronics industry is
`expected to grow from S l 5 billion last year to $35 billion by the mid 90’s.
`Convergence '88 explores ways that the application of electronic devices will
`change Where, how and what we will drive in the future, keeping in mind
`that cost, reliability and customer acceptance will determine which devices
`will become standard in tomorrow’s vehicles.
`
`Robert J. Eaton
`
`General Chairman
`
`Page 000003
`
`

`

`SPONSORS
`
`Vehicular Technology Society—institute of Electrical
`and Electronics Engineers, inc. (VTS-iEEE)
`and
`
`Society of Automotive Engineers, inc. (SAEi
`
`CO-SPONSORS
`
`American Society of Agricultural Engineers (ASAEi
`
`Society of Automotive Engineers of Japan (JSAE)
`
`Farm and industrial Equipment institute
`
`The institution of Electrical Engineers (UK)
`
`The institution of Mechanical Engineers (UK)
`
`Southeastern Miichigan Section-iEEE
`
`international Symposium on Automotive Technology & Automation ilSATA)
`
`Farm Equipment Manufacturers Association (FEMAi
`
`Page 000004
`
`

`

`EXHIBITORS
`
`Advance Electronics
`
`ALPS Electric (USA), Incorporated
`American Electronics
`
`Libbey - Owens - Ford Company
`
`Lucas Industries. Incorporated
`
`Magnavox Electronic Systems Company
`
`Amoco Performance Products, Incorporated
`
`Manu-Tronlcs, Incorporated
`
`AMP Incorporated
`
`Augat/Altalr, Incorporated
`
`AUTOSPLICE Incorporated
`
`AVX Corporation
`Bendlx Electronics
`
`Robert Bosch Corp.
`
`CTS Corporatlon
`
`Delco Electronics Corporation
`
`Dupont Company
`Electra-Metrics
`
`Ford Motor Company
`
`Frelghtllner
`
`Fujitsu Limited
`
`Futaba Corporation of America
`
`General Instrument Corporation
`w. Gunther GMbH
`
`Hughes Aircraft Company
`
`Hewlett Packard Components Group
`
`Hewlett Packard - Loglc Systems
`
`Honeywell Micro Switch Division
`
`Intel Corporatlon
`
`Intelligent Controls, Incorporated
`
`International Magnesium Association
`
`International Resistive Company
`ITT Cannon
`
`Japan Electronic Control Systems
`Company, Ltd.
`
`Kemet Electronics Corporation
`
`Keystone Carbon Company
`Kostal of America
`
`Microphoto Incorporated
`
`J.L. Montgomery Assoc., Incorporated
`Motorola
`
`Murata Erle North American, Incorporated
`NCR Micro Electronics
`
`NEC Electronics Incorporated
`
`Nippondenso Technical Center. U.S.A..
`Incorporated
`
`PA Consulting Group
`
`Panasonic Ind. Company
`Plher International
`
`Potter 8. Brumfleld
`
`Rayovac Corporatlon
`Robert Shaw Controls
`
`Rohlm Corporatlon
`Saturn Electronics and Engineering,
`Incorporated
`SGS-Thomson Microelectronics
`
`Sprague Electric Company
`SRI International
`
`STEP Engineering
`
`TDK Corporation
`
`Tektronix, Incorporated
`Texas Instruments
`
`3M/Conventlon Management
`
`Toko America, Incorporated
`
`Toshiba America, Incorporated
`TRW, Inc.
`Universal Photonlcs
`
`Weetech, Incorporated
`
`Page 000005
`
`

`

`TABLE OF CONTENTS
`
`SESSION I: WORLD OVERVIEW OF AUTOMOTIVE ELECTRONICS
`
`Chairman:
`Robert J. Eaton
`
`General Motors Europe
`Technology and Global Competitiveness ................................. (Oral Presentation Only)
`Robert A Lutz (Keynote Speaker)
`Chrysler Motors Corporation
`Electronics in Commercial Vehicles ....................................................................... I
`Dr. Hermann Eisele
`Robert Bosch GmbH
`
`Automotive Electronics In Passenger Cars ................................... . ........ . .............. i i
`Akio Numazawa
`
`Toyota Motor Corporation
`
`SESSION IIA: POWERTRAIN SYSTEMS
`
`Chairman:
`Robert M. Sinclair
`
`Chrysler Motors Corporation (Retired)
`Assistant Chairman:
`
`James C. Leslie
`
`Chrysler Motors Corporation
`
`Interactive Engine & Transmission Control
`Dipl. lng. Kurt Lorenz
`Bayerische Motoren \X/erke
`
`............. 25
`
`Electronically Controlled Continuously
`Variable Transmission [ECVT-ll] .......................................................................... 33
`Yoshiaki Kasai
`
`Fuji Heavy Industries Ltd.
`Powertraln Sensors and Actuators:
`Driving Toward Optimized Vehicle Performance ...........................................,....... 43
`James J. Paulsen
`
`Ford Motor Company
`
`Trends of Digital Signal Processing In Automotive .................. . ............................. 65
`Dr. Kun-Shan Lin
`
`Texas Instruments, Incorporated
`
`Engine-Transmission Integrated Control ............................................................. 77
`Yoshiaki Nakano
`
`Nippondenso Co., Ltd.
`
`SESSION "3: INTEGRATED SYSTEMS
`
`Chairman:
`
`Dr. Ryoichi Nakagawa
`Nissan Motor Co., Ltd.
`Assistant Chairman:
`Masazumi Sone
`
`Nissan Research & Development, Inc.
`
`The Next Step In Automotive Electronic Control .................................................. 83
`Shigeo Aono
`Nissan Motor Co., Ltd.
`
`Page 000006
`
`

`

`European Concepts for Vehicle Safety, Communication and Guidance ....................... 91
`Professor Dr. Peter \X/alzer
`Volkswagen AG
`
`Integrated Vehicle Control .......... ...................................................................... 97
`NeiIA. Schilke, Roger D. Fruechte, James H. Rillings, Brian S. Repa,
`Nader M. Boustany, A. Matthew Karmel
`General Motors Corporation
`
`The Systems Design Approach (Better Late Than Not at All) .................................. 107
`Joseph Gormley, David A. Maclsaac
`Ford Motor Company
`
`Designing Automotive Electrical/Electronic iE/E) Systems
`for Vehicle Assembly and Service ....................................................................... l 19
`Michael C. Cwiek
`Chrysler Motors Corporation
`
`SESSION IIC: VEHICLE ELECTRONICS
`
`Chairman:
`
`lng. Alessandro Barberis
`Magneti Marelli S.pA
`Assistant Chairman:
`Dr. Daniele Pecchini
`
`Magneti Marelli S.pA
`
`Future Displays in Europe ............................................................................... 127
`Dr. Holm Baeger
`VDO Adolf Schindling AG
`Millimeter-Wave Radars for Automotive Ulse ....................................................... l3l
`Takashi Sakamoto
`
`Fujitsu Ten Ltd.
`Automotive Electronics in the Car of the Future:
`
`Strategic Alternatives for the Vehicle Manufacturer ............................................. 147
`Frederick T. Tucker
`Motorola, inc.
`
`VlD and HUD Automotive Displays ................................................................... 153
`Harry J. King
`Hughes Aircraft Company
`
`John Ayres
`Delco Electronics Corporation
`
`Adaptive Controls Applied to Automotive Transmissions ............ (Oral Presentation Only)
`James G. Bender, Joseph H. Hunter
`General Motors Corporation
`
`SESSION III: BLUE RIBBON PANEL
`
`Oral Presentation Only
`
`SESSION IV: WORLD TECHNOLOGIICAL CHALLENGES
`
`Chairman:
`Dr. Malcolm R. Currie
`
`Hughes Aircraft Company
`Assistant Chairman:
`Thomas W. Evernham
`
`Delco Electronics Corp.
`
`New Technologies for the Trucking industry ............................. (Oral Presentation Only)
`Peter E. Rupp (Keynote Speaker)
`Daimler Benz of North America Holding Co., Inc. and Freightliner Corp. and Mercedes Benz Truck Company
`
`Page 000007
`
`

`

`DisplaySystems forAutomobiie ...........
`Hiromu Shiga
`Nippondenso Co., Ltd.
`
`.............................
`
`159
`
`Powertrain Management — An integrated Approach to
`Customer Satisfaction ................................
`.........
`David F. Hagen
`Ford Motor Company
`
`_
`(Oral Presentation Only)
`
`The Lotus Active Suspension System in Formula One .................. (Oral Presentation Only)
`Peter G. Wright
`Lotus Engineering
`Microelectronics Oroadis .......................
`Dr. George H. Heiimeier
`Texas instruments
`
`......
`
`......
`
`165
`
`SESSION VA: CHASSIS SYSTEMS
`
`Chairman:
`Ronald H. Haas
`
`Current Engineering and Manufacturing Services Staff
`General Motors Corporation
`Assistant Chairman:
`
`Stephen P. Stonestreet
`Current Engineering and Manufacturing Services Staff
`General Motors Corporation
`
`Electronic Control of Car Chassis —- Present Status and Future Perspective ....... . ....... 173
`Ryohei Kizu
`Toyota Motor Corporation
`Smart Power Semiconductors ....................... . ...................................... . ......
`Dr. Ruediger Mueller
`Siemens, AG —— Components Group
`
`189
`
`Antiiock Brake System & Traction Control ........................................ . .............
`Dr. lng. Norbert Rittmannsberger
`Robert Bosch, GmbH
`
`integrated Micromachined Silicon: Vehicle Sensors of the 1990’s?
`Ronald P. Knockeart, Robert E. Suiouff
`Allied-Signal, inc.
`
`integrated Chassis & Suspension Controls —
`Present and Future World of Chassis Electronic Controls
`Neil \X/. Ressier, David J. Patterson, Michael W. Soltis
`Ford Motor Company
`
`SESSION VB: VEHICLE COMMUNICATIONS
`
`195
`
`203
`
`213
`
`Chairman:
`
`Dr. Thomas Stanley
`Federal Communications Commission
`
`Assistant Chairman:
`
`Roger D. Madden
`Federal Communications Commission
`
`An Overview of AMTICS ............................................ . ........... . ...... . ...........
`Dr. Hiroyuki Okamoto
`Japan Traffic Management Technological Association
`Dr. Tsuneo Nakahara
`Conference on the Practicabiiity of AMTICS
`
`219
`
`Page 000008
`
`

`

`Vehlcle Communications in Europe ......................................................... . .......... 229
`Dipi. ing. Peter Bumann
`Ant Nachrichtentechnik GmbH
`
`National Networks lncludlng Satellite Service
`Dr. Carson E. Agnew
`GM Hughes Electronics Corporation
`
`.................. 237
`
`in-Vehicie Networks
`Frederick H. Phail
`lntel Corporation
`
`..... . ................................. [Paper Unavailable at Time of Printing)
`
`Vehicle Location by Satellite ............................................................................ 247
`Robert D. Briskman
`
`Geostar Corporation
`
`SESSION VC: COMMERCIAL VEHICLES
`
`Chairman:
`Dr. Hermann Eiseie
`Robert Bosch GmbH
`
`Assistant Chairman:
`Leo Weber
`
`Robert Bosch Corporation
`
`Electronics in European Trucks ......................... . .......
`Dr. lng. Ferdinand Panik
`Daimler-Benz AG
`
`..... . ......................... 251
`
`Application of Truck Electronics From the
`Viewpoint of the System integrator ................................................................. 259
`James W. Kruse, Robert D. Dannenberg
`Navistar international Transportation Corp.
`
`Automatic Control of Agricultural Machines ...............................
`Jitsuo Yoshida
`Kubota, Ltd.
`
`-
`
`..... . .............. 267
`
`Cummins Electronic Controls for Heavy Duty Diesel Engines ................................. 277
`Ronald B. Lannan, Albert E. Sisson, William G. Wolber
`Cummins Engine Company, inc.
`
`Overview on Electronic Controls for Vehicular Diesel Engines .............................. 295
`Masashi Shigemori
`Hino Motors, Ltd.
`
`Page 000009
`
`

`

`
`
`EXECUTIVE COMMITTEE
`
`General Chairman
`
`Robert J. Eaton
`General Motors Corporation
`
`Past General Chairman
`Frederick Z. Herr
`Ford Motor Company
`
`Convergence Founder and
`Co-Sponsorship Chairman
`Trevor 0. Jones
`International Development Corporation
`
`Vice Chairman
`Oliver T. McCarter
`General Motors Corporation
`
`Technical Chairman — Vehicle Electronics
`Dr. Malcolm R. Currie
`Delco Electronics Corporation
`
`Technical Chairman —
`Powertraln and Chassis
`Jerome G. Rivard
`Allied Signal, incorporated
`
`Technical Chairman — Commercial
`
`Dean P. Stanley
`Navistar International Transportation Corporation
`
`Technical Chairman - Australia and Asia
`Akio Numazawa
`Toyota Motor Corporation
`
`Technical Chairman — Europe
`Dr. Hermann Scholl
`Robert Bosch Corporation
`
`Exhibits Chairman
`
`Merrill L. Almquist
`General Motors Corporation
`
`industry-Reception Chairman
`Edward T. Mabiey
`Ford Motor Company
`
`Publications Chairman
`Donald \X/alkowicz
`General Motors Corporation
`
`Publicity Chairman
`J. Bruce McCristaI
`General Motors Hughes Electronics Corporation
`
`Finance & Registration Chairman
`Dr. Louis L. Nagy
`General Motors Corporation
`
`international Participation Chairman
`Alberto Negro
`Flat Auto 5.91“»
`
`Arrangements Chairman
`Joseph F. Ziomek
`TRW, Incorporated
`
`Banquet Chairman
`Todd L. Rachel
`
`TRWI Incorporated
`
`SAE Liaison
`Ronald L. Cutler
`
`TRW, incorporated
`
`IEEE Liaison
`Robert A. Mazzoia
`TR\X/ Automotive
`
`CHAIRMAN
`Trevor 0 Jones
`President
`International Development Corp.
`
`PANEL MEMBERS
`Stuart M. Frey
`Vice President for
`Technical Affairs
`Ford Motor Company
`
`Nagayuki Marumo
`Managing Director,
`Research & Development
`Nissan Motor Co., Ltd.
`
`Jerome G. Rivard
`Vice President and Group Executive
`Allied-Signal, inc.
`Dr. in . Klaus Stamm
`9
`Director Powertraln Development
`Volkswagen AG
`Dr. Hermann Scholl
`Chairman and President
`
`Robert Bosch Corporation
`
`Page 000010
`
`

`

`SUBCOMMIT'I'EE MEMBERS
`
`PUBLICITY COMMITTEE
`
`J. Bruce McCristal, Chairman
`GM Hughes Electronics Corporation
`
`Marilyn Y. Grant
`Deico Electronics Corporation
`Jack R. Harned
`
`General Motors Corporation
`Jane C. Mott
`
`General Motors Corporation
`
`PROGRAM & PUBLICATIONS COMMITTEE
`
`Donald \X/alkowicz, Chairman
`General Motors Corporation
`Patricia L. Seaton
`
`General Motors Corporation
`
`SESSIONS PLANNING COMMITTEE
`
`Oliver T. McCarter, Chairman
`General Motors Corporation
`David S. Grossman
`
`General Motors Corporation
`Ronald P. Knockeart
`
`Allied~Signal, incorporated
`Farrel L. Krall
`
`Navistar international Corporation
`Steven H. Jacobs
`
`Robert Bosch Corporation
`
`Kenji Ito
`Toyota Technical Center USA, inc.
`Gerald M. Sallus
`
`General Motors Hughes Electronics Corporation
`Howard G. Wilson
`
`General Motors Hughes Electronics Corporation
`
`INTERNATIONAL PARTICIPATION
`COMMITTEE
`
`Alberto Negro, Chairman
`Fiat Auto S.pA.
`
`John Felienberg
`Renault USA, Incorporated
`
`Eric Gough
`Lucas industries, incorporated
`Steven H. Jacobs
`
`Robert Bosch Corporation
`Kenichi Yoshida
`
`Nissan Research & Development, lnc.
`
`ARRANGEMENTS COMMITTEE
`
`Joseph F. Ziomek, Chairman
`TRw, incorporated
`
`Charles M. Boyd
`Ford Motor Company
`
`John Camp
`TRW, incorporated
`Ron Smith
`Motorola
`
`EXHIBITS COMMITTEE
`
`Merrill L Almquist. Chairman
`General Motors Corporation
`Susan K. Lawrence
`
`General Motors Corporation
`
`REGISTRATION COMMITTEE
`
`Louis L. Nagy, Chairman
`General Motors Corporation
`
`Charles M. Boyd
`Ford Motor Company
`
`William J. Fleming
`TRW, Incorporated
`Barbara J. Joslin
`
`General Motors Corporation
`Michael P. Nolan
`
`General Motors Corporation
`
`Diane Verbloegh
`3M
`
`Richard S. Maslowski
`
`Lawrence institute of Technology
`
`Page 000011
`
`

`

`INTEGRATED MICHOMACHINED SILICON:
`VEHICLE SENSORS OF THE 1990’S?
`
`Ronald P. Knockeart and Robert E. Suloufl
`
`Bendix Electronics Group, Allied Signal Corp. - 20650 Civic Center Drive - Southfield, MI 48086
`
`ABSTRACT
`
`competition and the need to
`Intense global
`satisfy increasing customer demands for higher
`quality and better performance
`are driving
`vehicle manufacturers
`to
`accelerate
`the
`creation of more
`and better vehicle control
`systems.
`
`affecting virtually all
`are
`systems
`These
`including steering,
`sus—
`vehicle functions,
`pension, and driver information, among others.
`
`these systems use silicon—based
`Virtually all
`to
`store
`control
`algorithms,
`electronics
`process
`information,
`and direct actuators to
`perform various
`functions.
`Although
`elec—
`tronics have been applied in many vehicles
`since the 1970’s,
`the
`rapid growth period
`spanning the time—frame from 1985 to the end
`of the century has been commonly referred to
`as the automotive “electronics revolution".
`
`unfolds,
`revolution
`electronics
`this
`As
`keeping
`sensor
`technology
`is not
`however,
`pace.
`Sensor designs continue to be based on
`dated technologies, with inbred limitations,
`that could limit
`the capabilities of newer,
`more
`sophisticated
`automotive
`electronic
`control systems.
`
`have
`Many electronics engineers and managers
`identified "silicon" as the sensor technology
`which will close this technology gap and usher
`in even greater application of these control
`systems.
`
`This paper will examine both the current state
`of
`traditional
`sensor
`technology and "state-
`of—the-art" silicon technology.
`Reasons why
`silicon sensors hold great promise for
`the
`future will
`also be
`addressed.
`Finally,
`predictions on the growth potential of silicon
`sensors will be discussed as well as potential
`impediments to progress that could delay that
`growth.
`
`CURRENT SITUATION
`
`While we are in the middle of almost explosive
`growth
`in the application of
`silicon-based
`electronics
`for
`automotive
`applications
`(Figure 1), we are not experiencing similar
`growth in silicon-based sensors.
`
`systems are being
`More silicon-based control
`introduced on vehicles with each new model
`year.
`These
`range
`from critical
`vehicle
`
`safe
`and
`engine control
`such as
`systems
`a
`protection
`to . comfort,
`convenience,
`sx
`stand~alone, driver
`information systems
`as navigation and blind—spot detection.
`(1-!
`
`$2000
`
`as; 2000
`53CD
`Ee
`5(3 1500
`0553¢Z
`053
`I...
`n:§ 1000
`Om
`u1>
`d“[1:
`E
`
`500
`
`1970
`
`1930
`
`1990
`
`2000
`
`Fig. 1. Automotive electronics content will
`reach $2000 by the year 2000.
`
`System Sensors
`
`All of these control systems use silicon—based
`electronics for implementation and nearly all
`have
`embedded microprocessors.
`The
`reasons
`for using silicon in these applications has
`been widely recognized by the industry:
`high
`reliability,
`low cost,
`small size and incom—
`parable flexibility. However, most of these
`systems still use sensors from the pre "elec~
`tronics revolution" era.
`The use of sensors
`is growing geometrically with the introduction
`of each new system.
`Today, many of
`these
`systems may use
`four,
`five, or
`even more
`sensors per application.
`
`For example, a typical Electronic Fuel Contro
`System uses sensors to gather information on:
`
`Crank/cam position
`. Manifold pressure
`. Coolant temperature
`Manifold air temperature
`. Throttle angle position
`. Engine knock
`Exhaust oxygen content
`
`* Numbers in brackets designate references listed at
`end of the paper.
`
`Page 000012
`
`

`

`system is also capable
`This class of control
`of sensing additional functions such as:
`
`Mass airflow
`EGR flow
`Fuel
`flow rate
`Valve position
`Cylinder pressure
`
`An Anti—lock Brake System may
`sensors for sensing:
`
`use five or six
`
`Individual wheel speed; four per vehicle
`Vehicle acceleration
`Hydraulic line pressure
`
`as
`such
`systems
`vehicle
`additional
`When
`Supplemental
`Inflatable Restraints, Adaptive
`Suspension and Traction Control
`(to name
`a
`few) are added to the current vehicle moni-
`toring sensors, as many as two to three dozen
`sensors could appear on an average car in the
`very near future.
`
`The automotive industry demand could expand to
`nearly 300 million sensors annually for
`the
`United States market
`and over one billion
`sensors for the world market.
`
`Sensor State of the Art
`
`today’s
`in
`used
`sensors
`The majority of
`automotive market are based on a variety of
`technologies which have been used for quite
`some time. Typically,
`these include:
`
`. Electromagnetics
`. Conductive films
`Heated-wire elements
`Electromechanical elements
`Piezoelectrics
`
`now use
`sensors
`pressure
`Certain
`elements for the sensing mechanism.
`
`silicon
`
`All of these sensors transfer information from
`one medium to another,
`and depending on how
`the transconduction (conversion of one form of
`energy into another) is implemented, could add
`cost or
`impose
`limitations
`on
`long
`term
`reliability.
`For example,
`a typical
`throttle
`-osition
`sensor
`converts
`throttle
`angle
`losition to an electrical voltage level via an
`lectrical
`film potentiometer.
`The wiper arm
`f the throttle potentiometer is mechanically
`»nnected to the throttle plate.
`As it moves
`'ross the potentiometer,
`it creates a change
`voltage output that is proportional
`to the
`sition of the throttle;
`and here is where
`problems arise.
`One moving element
`in
`-ect contact with another causes wear.
`The
`stant wear
`can
`produce
`failure
`in
`the
`sor which results in malfunction of
`the
`rol system.
`
`is added to the sensor when
`Additional cost
`signal conditioning or interface circuitry is
`required to convert one
`form of energy to
`another and allow the sensor to interface with
`the outside world.
`For example, an electro—
`magnetic sensor produces raw voltage levels
`or pulses. These are converted by electronics
`into digital
`format for compatibility with the
`host electronic control module.
`
`In addition to the need for signal condition—
`ing and interface electronics, current sensor
`technologies have other limitations and areas
`of concern.
`
`- Different sensor approaches use differ-
`ent
`technologies.
`Each requires a
`new
`learning curve and knowledge base for the
`application engineer.
`
`- Moving parts in contact with each other
`create wear problems
`(one example cited
`above).
`
`-
`
`Inter-element contact pressures can be
`sensitive
`to
`temperature,
`shock,
`and
`vibration.
`
`~ Part-toapart calibration consistency can
`be difficult
`to maintain with precision
`mechanical parts.
`
`require
`— Sensor multiplex systems may
`various
`add—on circuits to communicate
`with other vehicle systems.
`
`SILICON SENSORS
`
`Hicromachining
`
`for
`the potential
`has
`technology
`Silicon
`replacing most of the technologies currently
`used for
`sensor manufacturing today.
`This
`would alleviate many of the problems
`identi-
`fied above
`and permit
`one well-established
`technology to serve as
`the basis
`for most
`vehicle
`sensor
`designs.
`The
`significant
`benefits
`that
`could
`be derived from this
`"universal" technology will be discussed later
`in this paper.
`
`Silicon sensor designs can be created using a
`variety of manufacturing processes. One of the
`most promising is called micromachining which
`uses
`chemical
`processes
`to produce
`three
`dimensional mechanical
`structures in silicon
`(Figure 2).
`
`be made sensitive to
`can
`structures
`These
`specific physical phenomena such as accelera-
`tion or pressure
`by
`taking
`advantage
`of
`silicon’s special piezoresistive properties.
`For example, a micromachined cantilevered beam
`produces
`a minute
`resistance
`change when
`flexed by the force of acceleration. However,
`the output
`signal
`from this micromachined
`
`Page 000013
`
`

`

`MIMIRANII
`
`cAlfllLlVll
`
`IIAMI
`
`WWW'Illlllll
`
`lea-unann-
`
`IIIDBIU
`
`now "no!
`
`Fig. 2 Micromachined Structures
`
`that addi-
`(millivolts)
`is so small
`sensor
`tional electronic circuitry is necessary for
`signal conditioning and amplification.
`These
`electronic circuits
`are usually integrated
`circuit chips which are interconnected to the
`micromachined element.
`
`Integrated Silicon Sensors
`
`is created by
`integrated silicon sensor
`An
`IC chip(s)
`and
`eliminating the
`stand~alone
`producing the micromachined sensor element,
`signal
`conditioning and
`amplification cir-
`cuitry all
`on
`the
`same
`silicon substrate
`(6,7).
`But
`there are different degrees of
`sophistication for integrated silicon sensors
`(Figure 3). More than just signal condition-
`ing and amplification could be
`incorporated.
`Very large scale integrated circuits (VLSI)
`such as memory cells or microprocessors could
`be
`added on the same substrate to produce
`"smart”
`integrated
`silicon
`sensors with
`substantial processing power.
`This level of
`sensor
`sophistication would
`open
`up
`new
`application possibilities by providing:
`
`- Self calibration
`Customization through programmability
`Adaptability to changing environments
`Built-in diagnostics
`Off—line decision making
`Multiplex capability
`
`Manufacturing Process
`
`The process of creating silicon micromachined
`sensors is based on the same well-established
`techniques which are currently being applied
`in the integrated circuit
`industry.
`These
`techniques are used
`to build thousands of
`parts on
`a
`single wafer during
`a
`typical
`
`The silicon wafer is
`20-wafer batch process.
`for
`a
`sequence of
`the
`starting material
`process
`steps
`that use photolithography to
`define patterns (Figure 4).
`The same silicon
`wafers and patterning processes could be used
`to build either integrated circuits,
`sensors
`or
`a combination of
`the two.
`The pattern
`defined on the silicon controls the location
`of
`chemical
`processes which
`add materials
`(dopants)
`in precisely controlled methods to
`alter the electronic properties of the semi—
`conductor wafer.
`By stacking these patterns
`in layers,
`one
`atop the other,
`and using
`discrete chemical processes on each layer to
`remove
`portions
`of
`the
`exposed
`silicon,
`three—dimensional
`geometric
`designs
`are
`created to form transistors and other elec-
`tronic elements.
`
`sequence of patterns that are used to
`The
`define specific transistors
`(CMOS, Bipolar)
`grows in complexity as higher circuit perfor-
`mance is required.
`The minimum pattern size
`and
`the
`number
`of patterns
`also
`relates
`directly to manufacturing cost. Therefore,
`higher
`performance
`transistors
`cost more.
`Standard integrated circuits (ICs) use 7 to 8
`patterns and minimum feature sizes from 2 to 5
`microns.
`The higher performance, advanced IC
`processes use
`12
`to 14 patterns
`and
`1.25
`micron minimum sizes.
`Now emerging in the
`semiconductor industry are still more complex
`16
`to
`18 pattern sequences
`that
`combine
`bipolar and CMOS
`to take advantage of both
`types of transistors.
`
`sub-
`Silicon micromachining technology uses
`stantially the same pattern definition tech-
`niques
`now used
`by the IC industry.
`The
`minimum
`pattern
`sizes
`for
`sensors
`are
`typically 5 to 20 microns with 4 to 6 patterns
`required to build most micromachined sensors.
`The addition of a pattern that allows etching
`or micromachining of the silicon is all
`that
`is necessary to build these sensors.
`Early
`silicon-based pressure sensor designs used the
`typical base diffusion manufacturing process
`for bipolar
`IC’s and then added a diaphragm
`etch to micromachine the sensor as the last
`step.
`
`The combination of an integrated circuit with
`a micromachined sensor on the same substrate
`can
`be
`accomplished
`by
`adding
`the
`sensor
`patterns and processing sequences at
`the end
`of the integrated circuit process.
`There are
`compatibility issues that must be addressed
`but the technical feasibility has already been
`proven
`(Figure 5,6).
`In
`this
`integrated
`sensor approach an appropriate starting wafer
`is selected that will
`allow both integrated
`circuit and sensor processes to be performed
`on
`it.
`The
`integrated circuit patterns and
`their sequence of processes are used first to
`construct a functional circuit. After the It
`processes are built
`into the wafer,
`sensor
`patterns and their associated chemical pro-
`
`205
`
`Page 000014
`
`

`

`INTEGRATED SENSOR
`ARCHHECTURE
`
`O COMBINED SENSOR TECHNOLOGY
`AND VLSI TECHNOLOGY
`0 STANDARD INTERFACE WITH
`APPLICATION SPECIFIC SENSOR
`
`DIGITAL
`OUT
`
`OUTPUT
`INTERFACE
`BUS
`MUX
`leT/REC
`
`SIGNAL AND
`IDENTFICATION
`CALIBRATION
`AND
`IDENTIFICA'VIOH
`“‘5"
`LEVEL
`PROGRAMABLE
`8'9"“5 DIGITAL TRIM
`CONTROLLER
`FUNCTIONS
`VOL'I'S
`FREQ.
`DIGITAL
`
`LOW
`SIGNALS
`LEVEL
`
`INTERFACE
`CIRCUIT
`AMPLIFICATIOR
`COMPENSATION
`CONVERSION
`
`FILTERING
`
`upu'r
`PHYSICAI.
`VARIABLES
`
`SENSOR
`ELEMENT
`PIEZORESISTIVE
`CAPACI‘I’WE
`PIEZOELECTRONIC
`MAGNETIC
`THERMAL
`MICROMACHINEB
`STRUCTURES
`
`O ARCHITECTURE MATCHED
`TO APPLICATION
`O SYSTEM DESIGNED TO
`SENSOR LEVEL
`
`Fig. 3
`
`Integrated Sensor Architecture
`
`
`(I)
`
`
`
`
`IC PHOTORESIST PATTERNS
`CROSS-SECTIONS OF CHEMICAL PROCESSES
`
`
`
`
`SILICON PHOTOMASK PROCESS
`
`
`WAFER FOUNDRY
`
`INTEGRATED CIRCUIT PROCESSING
`
`
`
`SENSOR BACKSIDE ETCHING
`
`
`SENSOR PROCESSING
`
`Fig. 4
`
`Semiconductor Processing
`
`206
`
`Page 000015
`
`

`

`the sensor
`The design of
`cesses are added.
`patterns depends upon the sensing mechanism.
`If a strain gauge type piezoresistive mecha-
`nism is desired,
`then patterns and processing
`to provide specific resistors are added.
`If a
`capacitive sensing mechanism is desired then
`micromachined structures that permit
`capaci-
`tance
`changes are patterned.
`The variety of
`sensing mechanisms
`and
`the
`corresponding
`patterns
`and processing required call
`for
`careful engineering evaluation that
`includes
`assessment of
`cost
`and
`reliability issues
`(8-14).
`
`Motorola
`
`Honeywell
`
`
`-SSED
`
`Fig. 5
`
`Integrated Pressure Sensor
`
`Fig. 6
`
`Integrated Silicon Accelerometer
`
`Vehicle Application Requirements
`
`types of vehicle environments and oper-
`What
`ating conditions will
`sensors of the 1990’s
`experience?
`
`207
`
`automotive electronic
`The proliferation of
`systems will
`translate into less available
`packaging space.
`Therefore,
`smaller
`sensor
`components,
`system repartitioning and multi-
`ple-use sensors will become highly desirable.
`
`The trend toward more aerodynamic design will
`reduce or eliminate grill
`sizes which will
`restrict air flow through the engine compart-
`ments.
`This will
`raise engine
`compartment
`temperatures. Electronic modules and sensors
`will have to survive in a more hostile envi-
`ronment.
`
`The use of Vehicle multiplex systems will
`accelerate.
`This will affect virtually all
`electronics modules and sensors which will be
`required to communicate with each other over
`common data busses (15-18).
`
`Tighter emissions laws are expected which will
`require more
`precise measurement,
`faster
`response times,
`and finer control of combus-
`tion processes.
`Sensor performance require-
`ments will have to increase in order to meet
`these demands.
`
`Automotive Industry Requirements
`
`in
`improvement
`constant
`toward
`trend
`The
`system and component reliability will contin—
`ue,
`fueled by customer expectations.
`Suppli-
`ers will
`be expected to apply the systems
`approach to ensure optimum performance,
`long
`term reliability and
`fail
`safe operation.
`This
`trend will
`have
`a direct
`impact
`on
`sensors which have been perceived by many as
`the weakest link in today’s automotive control
`systems.
`
`System diagnostics will continue to be a major
`concern.
`The high cost of component replace-
`ment will
`require improved methods of accu-
`rately identifying a failed or malfunctioning
`component.
`As
`a result, electronic modules
`and
`electronics—based
`sensors will
`require
`some form of diagnostic capability -~ either
`self-generated or stimulated from an external
`source.
`
`The trend toward many different vehicle market
`segments will
`require much more
`flexibility
`from standardized systems and components such
`as sensors to keep costs down. This
`flexi-
`bility must
`be designed
`into the
`sensor,
`perhaps
`in the
`form of electronics memory
`with
`accompanying
`software which
`can
`be
`tailored to specific vehicles.
`
`POTENTIAL OF INTEGRATED SILICON SENSORS
`
`As cited earlier, current vehicle sensors use
`a wide variety of
`technologies and manufac—
`turing processes.
`Each requires a specific
`knowledge base by designers for each sensor
`
`Page 000016
`
`

`

`type in order to create an effective system
`application.
`This often demands
`long lead
`times for implementing new sensor applications
`due to “learning curve" requirements and the
`need to develop confidence in the design.
`
`can minimize or
`Integrated silicon sensors
`inherent
`problems
`eliminate many of
`these
`associated with current sensor
`technologies;
`and,
`in doing so,
`reduce
`the growing
`gap
`between systems
`technology and sensor
`tech—
`nology (19-26).
`
`System designers will have one basic technol-
`ogy
`to work with
`rather
`than many.
`The
`characteristics and knowledge base for silicon
`are already well
`known
`and the material
`is
`readily compatible with existing silicon based
`electronic modules.
`The only real variable is
`the specific implementation of the base sense
`element.
`System designers will
`focus
`their
`efforts on meeting the performance and reli-
`ability requirements
`of
`these
`elements
`to
`assure
`system integrity.
`In
`addition,
`the
`technologies associated with silicon materials
`and manufacturing processes are probably the
`most advanced of any in the world. This well
`established technology,
`Supported
`by
`huge
`investments
`in
`sophisticated manufacturing
`facilities,
`can be used to manufacture the
`integrated silicon sensors of
`the
`1990’s.
`Silicon—based sensor technology would provide
`the same benefits as those currently associ-
`ated with standard integrated circuits; high
`reliability,
`low cost,
`small
`size and high
`performance.
`However,
`there are many other
`benefits that are not
`immediately apparent.
`
`to unusually
`exposed
`are
`sensors
`Vehicle
`hostile environments, especially when located
`under hood.
`They
`are expected to survive
`severe shocks, vibrations, high temperatures,
`dust,
`and corrosive fluids over
`the life of
`the vehicle.
`Many
`of
`the properties
`of
`silicon make
`this material
`particularly
`adaptable to these hostile environments.
`The
`exceptional strength of silicon (stronger than
`stainless steel) makes it particularly adapt—
`able to applications exposed to severe
`shock
`and vibration. Another
`important character-
`istic of
`silicon
`is
`the
`elimination
`of
`hysteresis. Unlike many of the materials used
`for sensing elements today, silicon does not
`exhibit hysteresis
`or
`changes
`during
`the
`transduction process no matter how many times
`it is flexed. Silicon can be doped with other
`materials to produce many unique properties
`such
`as
`Piezoresistive
`effects
`and
`micr