ELSEVIER
`
`Sensor:, and Actuators A 66 ( 1998) 76-87
`
`SEN$p?S
`ACFIJA~ORS
`A
`
`PHYSICAL
`
`-
`
`Silicon mirrors and micromirror arrays for spatial laser beam modulation
`
`Steffen Kurth *, Ramon Hahn, Christian Kaufmann, Kersten Kehr, Jan Mehner, Udo Wollmann,
`Wolfram D(itzel, Thomas Gessner
`
`Received
`
`7 October
`
`1997: accepted
`
`18 November
`
`1997
`
`Abstract
`
`arrays made of mono-
`of mirrors and micromirror
`investigations
`and experimental
`technology
`the design,
`deals with
`contribution
`This
`crystalline silicon. Electrostatically
`operated
`two-directionally
`deflecting mirrors and mirror arrays for continuous scanning with working
`frequencies between several 100 Hz and 200 kHz are presented. The modified BESOI
`technology used and the experimental-data-based
`method to Improve the accuracy of model parameters for simulations and to determine
`the cross-coupling between array cells are new in the
`lield of micromechanics. Furthermore,
`results of application-related
`experiments of laser projection are given.
`0 1998 Elsrvier Science S.A.
`All rights reserved.
`
`Kqlr~n’s:
`
`Micromirror
`
`arrays; Two-directional
`
`deflection: Modified
`
`BESOI
`
`technology
`
`1. Introduction
`
`Various movable optical mirrors made of metal [ 1,2],
`polycrystalline silicon [ 3,4] or monocrystalline silicon [ 5,6]
`as mechanical material have been presented in the last few
`years. Technological approaches for monocrystalline micro-
`mirror arrays have been proposed [6]. This paper will
`describe the design of mirrors and mirror arrays with polished
`light-reflecting surfaces and electrode gaps down to 3 f-lm. It
`includes results of simulation improvement and the experi-
`mental analysis of intercellular coupling within mirror arrays,
`a field with hardly any published material.
`Application-dependent requirements concerning light-
`deflecting devices often include a relatively large optical
`active area of a few square millimetres, a high mechanical
`tilting angle up to 10” and upper working frequencies in the
`range of 100 Hz to several hundred kilohertz, In this case, the
`drawback of electrostatically operated tilting mirrors is the
`high driving voltage of up to 1000 V because of the mechan-
`ically necessary large electrode gap and high mass moment
`of inertia due to the size of the mirror plate. Generally, two
`approaches have been pursued. When operating at or close
`to the resonance frequency in order to magnify the amplitude
`nearly by the quality factor. the actuator performs a harmonic
`oscillation. Dividing the optically active area into smaller
`
`* Conespondinf
`
`author. Tel.: + 19 371 53 1 32 20; fax: + 19 37 I 53 I 32
`
`59.
`
`09244247/98/$19.00
`P((SO923-32~7197)01731-7
`
`0 1998 Elsevier Science S.A. AH rights
`
`reserved.
`
`parts, however, allows a micromirror array to be built up with
`a smaller electrode gap and less mass moment of inertia.
`Smaller dimensions lead to higher natural frequencies, large
`tilting angles, lower driving voltages and less translatory
`deflection, as shown in Fig. 1. However, the reduced optical
`area of the mirror cell may turn out to be a disadvantage for
`some applications. Micromirror arrays consisting of several
`small mirror cells provide a large optical area combined with
`the advantages of small mirror cells.
`
`2. PrincipIe of operation
`
`The bulk-micromachined KOH-etched mirrors and mirror
`arrays (Fig. 2) consist of 30 km thick silicon plates, evapo-
`rated with reflectivity increasing metal (Al or CrAu) and
`suspended by silicon beams in a frame or in a mesh grating
`in the case of an array. The size of the light-reflecting area of
`the mirror or of each mirror cell is 3000 km X 3000 IJ-m with
`an electrode gap of 370 km.
`The 5 p.m thick mirror plates and elastic beams of the
`micromirror arrays in modified BESOI technology (Fig. 3)
`contain a reflecting part on each mirror 50 p,rn X 250 p,m in
`size. The size of the electrode gap is 3 pm.
`Six degrees of freedom exist assuming the mirror plate as
`a rigid body. Practically, only two degrees of freedom have
`to be taken into account when predicting the behaviour of
`one actuator cell. The first mode shape is the rotation of the
`
`Petitioner Ciena Corp. et al.
`Exhibit 1034-1
`
`

`

`voltage)
`
`(equal
`angle
`Tilting
`frequency
`Torsional
`voltage
`(equal
`Driving
`Translatory
`deflection
`
`tilting angle)
`
`is often very
`in further degrees of freedom
`the movement
`small and should be neglected to simplify
`the calculations.
`Eq. ( 1) describes
`the model of a single mirror cell (see
`Fig. 4) as a resonator with
`two degrees of freedom:
`
`o’.or
`scale
`Dimensional
`inRuence
`of dimensions
`
`O'.l
`factor
`on mirror
`
`properties.
`
`Fig.
`
`I. The
`
`moving plate. The electrical force produces an additional, in
`some cases undesired,
`translatory deflection of the mirror,
`which
`is directed to the driving electrodes. The amplitude of
`
`the mass moment of inertia J. the mass IR, the damping
`with
`coefficients c, and c,, the electrostatic coupling coeflicients
`eri and e,,, the bias voltages rlhi and the driving voltages ~7~.
`The natural frequencies without damping are nearly given by
`
`Outer
`
`frame
`
`Mesh
`
`grating
`
`Glass
`
`top
`
`Bondpad
`
`region
`
`Distance
`
`Actuator
`
`wafer
`
`wafer
`
`Glass
`
`bottom wafer
`
`Isolation
`Fig. 2. SEM photograph
`
`stack and driving electrodes
`of the back of u two-directional
`
`mirror
`
`and of a mirror
`
`array
`
`in bulk micromechanics
`
`and cross-sectional
`
`schematic
`
`view.
`
`Mirrw
`
`strip
`
`Torsion
`
`beam
`
`Supporting
`
`post
`
`Bondpad
`
`Sondpad
`
`region
`
`Back-thinned
`silicon
`layer
`
`Sacrificial
`
`layer
`
`Etch slop
`
`layer
`
`CVD oxide
`
`Thermal
`
`oxide
`
`Carrier
`Fig. 3. SEM photographs and cross-sectional schematic view of a mirror array in modified BESOI technology.
`
`Petitioner Ciena Corp. et al.
`Exhibit 1034-2
`
`

`

`[ 71, where I, and w,, are lateral plate dimen-
`( 1 /w: + l/l,,:)
`sions, p is the ambient pressure, T,,,, is the effective viscosity
`[Sj and d is the plate separation, no phase shift occurs.
`Assuming
`relatively small angular deflections,
`the ratio of
`gas reaction
`force and plate velocity can be considered as
`constant. Depending on the degree of freedom,
`these ratios
`describe damping coefficients of translatory and rotatory
`oscillations.
`In the case of plates that are large compared with the elec-
`trode gap, the gas-pressure change P can be analysed by using
`the well-known
`Reynolds gas-film equation:
`
`(7)
`
`frequency
`the critical
`frequencies are below
`If the working
`wc, the time-dependent
`term of Eq. (7) can be neglected and
`we get a Poisson equation, which can be readily solved for
`simple geometries
`[ 71.
`Calculated results are:
`
`78
`
`Fig. 1. Schematic
`
`of the CKM
`
`section and working
`
`principle
`
`of a single cell.
`
`for rotary motion and
`
`24 EI
`I~lmLl’,,tl~pS,
`
`(2)
`
`(3)
`
`for translatory motion without any electrostatic held, where
`the shear modulus is G,,,, the torsion moment is I,, the Young’s
`modulus
`is E, the area moment of inertia is I. the thickness
`of the silicon movable part is th and the specific weight
`is pSl.
`The electric field of the applied bias voltage causes adisplace-
`ment-depending
`torque and decreases the elasticity k of the
`spring-mass
`oscillators
`to
`
`The natural frequency is decreased as well. The coefficients
`for electrostatic
`translating
`force and rotating
`torque can be
`expressed by
`
`(4)
`
`where A is the plate area, K, and Kr depend on the aspect ratio
`1,,,/~~,,, (K,=O.43
`[9] and K,= 17.61X IO-’
`for square
`plates).
`frequencies are above wC, an analogy of
`If the working
`Reynolds equation to the heat-transfer equation allows any
`plate shape and oscillation modes to be analysed with com-
`mercial
`finite-element
`tools like ANSYS. The local plate
`velocity must be replaced by the heat-generation rate and the
`temperature response has to be transformed
`into the pressure
`distribution.
`In the cabe of large air gaps or non-free outstream condi-
`tions on the plate edges, Reynolds gas-film equation
`is not
`suitable for analysing the fluid Bow. Finite-element
`tools with
`fluid-dynamic
`capabilities are necessary
`to analyse micro-
`mirror arrays separated by a suspending grid (Fig. 5). Sim-
`ulations show a substantial pressure gradient outside the mir-
`ror plate. Therefore. accurate results for these structures can
`be found by using a time-consuming
`numerical
`fluid-flow
`analysis with FLOTRAN.
`Damping coefficients
`and the
`cross-coupling
`to the adjacent cells are calculated iteratively
`by the real part of the integrated pressure distribution on
`harmonic oscillating plates.
`
`Electroshtically
`
`excircd minor
`\
`
`Fhd velocity
`plot of
`the
`fluid Row around
`
`I
`
`Sus;pcnhing grid
`
`a micromirror
`
`array
`
`using
`
`Fig. 5. Velocity
`FLOTRAN.
`
`et2 = 4d[ - ( w,,,/2) Q + Ii]
`
`(5b)
`
`(6a)
`
`(6b)
`
`respectively, with
`II.
`
`the tilt angle a~#0 and the electrode gap
`
`The damping coefficients e, and c,., the stiffnesses k, and
`k,, the driving
`force F,,, and the driving
`torque A4,, can be
`calculated using the finite-element method as well.
`The surrounding air causes
`forces and moments on the
`mirror plate depending on the deflection and on the velocity.
`These forces and moments act as a mechanical damper. In
`some cases. if there is a significant phase lag between
`the
`plate velocity and the gas reaction force, qrv, the surrounding
`gas additionally acts as a spring ( qFv > 0) or as an inertial
`mass ( (rev < 0).
`Most of the mechanical energy dissipates in the viscose air
`film within
`the electrode gap. If (1-x /,,l.~t’,,, and ifthe working
`frequency
`is less then a critical frequency o, = *PC?/ 1277,,t
`
`Petitioner Ciena Corp. et al.
`Exhibit 1034-3
`
`

`

`The whole array or a part of it has to be described as
`numerous single cells combined with elastomechanic cou-
`pling between them, additional ‘damping’ coefficients
`forthe
`fluid-dynamic
`coupling and further electrostatic
`coupling
`coefficients
`to describe the electrostatic cross-talk.
`
`3. Fabrication
`
`19
`
`four different wafers, aglass
`The actuator design comprises
`top wafer, an upper silicon distance wafer, a silicon actuator
`wafer and a glass carrier wafer. The actuator wafer and the
`upper distance wafer are fabricated
`in silicon bulk micro-
`machining using double-side-polished
`3 inch silicon wafers.
`The silicon membranes situated in the actuator wafer and the
`frames between
`them are patterned by anisotropic etching
`with KOH using SiO, and Si,N, as etch mask. The upper
`distance wafer
`is etched anisotropically
`in two steps in order
`to define spaces for the glass cover and the mirror clearance.
`Silicon fusion bonding (SFB)
`is used to connect the silicon
`wafers
`(distance and actuator wafer). A metal (aluminium
`or gold)
`is deposited on both sides of the wafer compound
`using sputter masks. This layer serves as a reflector on the
`mirror front side and as a conducting and stress compensation
`layer on the mirror back side. Fabricating
`the glass carrier, a
`I SO nm Si3N4 layer is deposited on the glass carrier wafer by
`using PECVD
`in order to fabricate a barrier between the glass
`and the driving electrodes
`( 1 p,m aluminium), which are
`prepared on top of the nitride. Above these electrodes, a layer
`stack consisting of PECVD Si,N,, PECVD SiOz and PECVD
`Si,N,
`insulates the structure against the air, since during the
`actuator operation a relatively high voltage is applied. The
`actuator wafer
`is attached to the @ass carrier wafer by anodic
`bonding.
`
`3.2. Mirror nrrq
`
`in modiJied BESOI technology
`
`a thermal oxidation and a deposition of CVD
`Following
`oxide, the driving electrodes are applied on and patterned on
`the carrier wafer. A further CVD oxide, deposited on this
`wafer and on an additional blank active wafer. serves as
`
`W’Glasscamer
`
`Electrodes
`
`(I pm Al)
`
`Fig. 6. Measurement
`
`set-up
`
`for
`
`the frequency
`
`response
`
`layer and silicon fusion bondable surface. Before
`sacrificial
`silicon fusion bonding, the wafer containing electrodes must
`be polished in order to remove the in-oxide-transferred
`elec-
`trode topology. The active wafer
`is thinned down to 5 IJ-m by
`KOH wet etching and polished by chemical mechanical pol-
`ishing. After coating the surfaces with the reflection layer and
`protecting
`them, the mirrors are structured by plasmaetching
`and released by wet etching of the sacrificial oxide.
`
`4. Characteristics
`
`4.1. Behwiorw measwernerzt
`
`leads to
`functions
`transfer
`Measurement of the frequency
`some characteristic values: natural frequencies and damping,
`eigenfrequencies, d.c. transfer
`rates and transfer
`rates at a
`frequency near the natural frequencies. A Doppler
`interfe-
`rometer detects the rotation concerning
`the X- or y-axis and
`the out-of-plane motion separately (Fig. 6). Statistical meth-
`ods of signal processing are used to calculate the frequency
`response function
`in order to decrease the noise. Results are
`shown
`in Fig. 7 and in Table 1.
`The reproducibility
`of the angular deflection has been
`tested with an electronic speckle interferometer. The position
`of the mirror cells was detected after switching off and on a
`dc. voltage and after exciting at the resonance
`frequency
`(harmonic oscillation with 7”) with a d.c. voltage. It has been
`
`1
`
`g 0.1
`I.
`
`0.01
`
`100
`
`(left);
`
`frequency
`
`200
`
`300
`Frequency
`response
`function
`
`500
`
`4oTi
`[kHz]
`of an array
`
`600
`
`in modified BESOI
`
`technology
`
`Fig. 7. Natural
`(right).
`
`frequencies
`
`1.5
`Frequency
`and mode shapes of an array
`
`2.5
`
`2.0
`[kHzl
`in bulk micromechanics
`
`3.0
`
`Petitioner Ciena Corp. et al.
`Exhibit 1034-4
`
`

`

`1
`Tabie
`Results of an experimental
`shapes
`
`modal analysis.
`
`natural
`
`frequencies
`
`and mode
`
`observed that the error of tilt is less than 0.003” according to
`the tilt before switching
`the driving voltage and before driving
`at the resonance frequency.
`
`4.2. Model
`
`evnlzmtim
`
`One of the goals of the experimental characterization of
`mirrors and mirror arrays is to evaluate theoretical models
`describing the behaviour including the fluid, elastomechanic
`and electrostatic coupling mechanisms between several mir-
`ror cells and between several degrees of freedom. The matri-
`ces for inertia, damping, stiffness and force in Eq. ( 1) may
`contain appropriate parameter values (e.g..
`the mass
`moments of inertia) and, of course, more discrepant values
`
`0.001
`
`1. IO”
`
`(e.g., all damping coefficients). The parameter values of the
`model are adapted by the method of least squares. A correc-
`tion algorithm with multiple steps is used (discussed in Ref.
`[ IO] ) . In this way, an immediate evaluation of the calculated
`damping and fluid-caused coupling becomes possible.
`Results are shown in Fig. 8.
`
`5. Experimental
`
`A relatively large mechanical tilting angle of up to 10” is
`achieved by driving the single 2D mirrors at the resonance
`frequency. The electrode voltage drives the mirror synchro-
`nously in both directions with a phase lag of 90” between the
`directions. The voltage ofthe mirror modulates the amplitude
`of the movement to scan a spiral in a plane or wind on a
`cylindical screen. Modulating the laser beam intensity, a laser
`scanning display is accomplished. Fig. 9 shows the experi-
`mental set-up and Fig. 10 a photograph of the resulting scan-
`ning pattern.
`
`5.2. Closed-loop cmtrol
`
`For several applications it is suitable to operate below the
`resonance frequency to generate arbitrary scanning patterns.
`The angular deflection is of course limited by the mechanical
`
`of the screen with symbols
`Fig. 10. Photograph
`acanning
`laser projection
`system.
`
`projected
`
`by
`
`the pattern-
`
`1. ,0’,000
`
`1050
`
`1100
`[Hz]
`Frequency
`non-
`and an adjacent
`of an excited
`functions
`response
`Fig. 8. Frequency
`data compared
`to the data of an experimentally
`excited array cell, simulation
`enhanced model and measured
`data points.
`
`1150
`
`1200
`
`Static characteristic
`
`Unstable
`
`worki
`
`Fig. 9. Experimental
`
`m-up
`
`for pattern-scanning
`
`laser projection.
`
`I I. Dependency
`Fig.
`resonator.
`
`of the static characteristic
`
`and natural
`
`frequency
`
`of rhe
`
`Petitioner Ciena Corp. et al.
`Exhibit 1034-5
`
`

`

`LZZi
`
`Posiliin
`
`sensitive
`
`devica
`
`8
`
`90
`
`Fig.
`
`12. Experimental
`
`set-up of the closed-loop
`
`system with detection
`
`of the position
`
`[ms]
`Time
`at one mirror
`
`cell and driving
`
`of all
`
`properties, but even more strongly by an unstable working
`point caused by the electrostatic
`field. It is necessary tosatisfy
`two conditions. The electrostatic
`torque equals the torque of
`the torsion beams and the derivative of the electrostatic
`torque
`must be less than the derivative of the spring moment. Elec-
`trostatic
`forces and torque increase more than proportionally
`if the electrode gap or the tilting angle decreases. The equi-
`librium of the moments or the forces cannot be preserved. A
`characteristic of this is that the stiffness of the electrome-
`chanical system equals zero. The deflection-dependent elec-
`trostatic moment and force attract the mirror more than the
`withstanding
`spring and it is not possible to drive the actuator
`in this region. Fig. 11 shows
`the moment of the electrome-
`chanical system as a function of the tilting angle with the bias
`voltage as parameter.
`Controlling
`the actuator position is a promising method to
`diminish the positioning
`time, to reach deflections outside the
`stable working
`range and to arrive at a high positioning accu-
`racy. The angular position of one cell can be detected as the
`input signal for the controller. All the other mirror cells are
`driven without any feedback
`in accordance to the likelihood
`of the cells within a single array. A semiconductor
`laser and
`an optoelectrical position-sensitive
`device are used to detect
`the angular position of the actuator in our experimental set-
`up. Fig. 12 shows schematically
`the set-up and the measured
`angular displacement at several mirror cells. Considering
`the
`high quality factor of the plant, we could find that the resulting
`scan is very sensitive
`to the controller parameters. It is useful
`to adjust the parameters empirically
`following
`the initial pre-
`dicting procedure.
`
`the
`with an error of less then 0.003” becomes possible with
`sil-
`presented technological approach using monocrystalline
`icon as the material for the mirror plates and the hinges. A
`model with precalculated parameters
`is used to simulate the
`electromechanical behaviour of the mirror arrays. Analytical
`relations express
`the stiffness of the beams, the electrostatic
`loads and the damping in the case of small electrode gaps. A
`finite-element model analysis
`involving
`inertia and
`the
`squeeze effect
`leads to more accurate values of the Auid-
`caused cross-coupling
`and of the damping in large electrode
`gaps. Calculated values
`for damping and cross-coupling
`match very well with experimentally determined data. It is
`necessary
`to drive all the mirror cells of an array synchro-
`nously
`to get a large optically active area for
`laser beam
`steering. A sufficient homogeneity of the cell properties, such
`as the electrode gap, the thickness of mirrors and torsion
`beams, is required for this. Operating the mirror arrays with
`a controller
`in a closed loop reduces the oscillations due to
`the low damping.
`
`Acknowledgements
`
`the support by the
`like to acknowledge
`The authors would
`DFG
`(Deutsche
`Forschungsgemeinschaft),
`Sonderfor-
`schungsbereich 379, and the Federal Ministry
`for Education
`and Research (contract 16SV397/8).
`
`References
`
`6. Conclusions
`
`is a promising way to enlarge
`Scaling down the dimensions
`the tilting angle and to reduce the driving voltage of analogue
`operating micromirrors which work at frequencies up to 200
`kHz. Electrostatic pull-down, break-down
`voltage and tech-
`nological
`limitations
`restrict
`the increasing of the tilt in ana-
`\ogue operation. High reproducibility of the scanning position
`
`timely
`and MEMS:
`processing
`in Micromachining
`and Micro-
`Applied
`Science
`and Engineerins
`
`light
`Diyital
`Hornbeck,
`[ I ] L.J.
`future,
`for a bright
`convergence
`‘95. SPIE Thermatic
`fabrication
`Series, Austin, TX, Oct. 1995.
`Infrared
`U. Hofmann,
`[2] A. Wagner,
`K. Reimer,
`A. Maciossek,
`angle, Tech,
`micromirror
`array with
`large pixel size and large deflection
`(Transducers
`Digest, 9th Int. Conf. Solid-State
`Sensors and Actuators
`‘971, Chicago,
`IL, USA,
`16-19
`June. 1997, vol.
`I. pp. 75-78.
`[ 31 M. Fischer, M. NBgerle, D. Eichner, C. SchGllhorn,
`R. Strobe], Sensors
`and Actuators A. 52 ( 1996) 140-144.
`
`Petitioner Ciena Corp. et al.
`Exhibit 1034-6
`
`

`

`0. Solgard, K.Y. Lau,
`141 M.H. Kiang, D.A. Francis,C.J.Chnng-Hasnaiil,
`for
`raster-acanning
`R. Muiler.
`Actuated
`polysiiicon
`micromirrors
`diaplays.Tech.
`Digeat.9thInt.
`Conf. Solid-StnteSerlsorsandActuators
`(Transducers
`‘97). Chicago.
`IL. USA,
`16-19
`June. 1997. vol.
`323-326.
`M.
`Neifeld.
`M.A.
`A. Garcia-Vaienzula,
`[S] P. Hsiang.
`toraionai mirror
`50 p.m X 250 pm silicon
`Micromachinrd
`Integrated
`SPIE
`Proc..
`processing,
`optical
`signal
`vol. 1793. 1992, pp. 190-198.
`Microstructures.
`S. Kurth. K.
`[ 6 j T. Geasner, W. Dbtzel, D. Billep. R. Hahn, C. Kaufmann.
`Kehr, C. Steiniger,
`U. Wollmann,
`SPIE Proc., 3005
`( 1997) 256-305.
`171 W.S. Griffin,
`H.H. Richardson,
`S. Yamranami,
`A study
`of
`fluid
`squeeze-tilm
`damping.
`J. Basic Eng., Trans. ASME.
`(June)
`i 1996)
`15 1156.
`J. Lahdmperii.
`H. Ku&ma.
`[ 81 T. Veijola.
`A. 18 ( 1995 1 239-218.
`Actuators
`in solid-state
`[91 J. Starr, Squeeze-film
`damping
`Solid-State
`Sensor and Actuator Workshop.
`USA. 1-7 June. 1990, pp. 4117.
`[ 101 S. Kurth. W. Dijtzei, Sensors and Actuators
`
`I. pp,
`
`Tabib-Azar,
`arrays
`for
`Optics
`and
`
`T. Ryhiinen.
`
`Sensors and
`
`IEEE
`accelerwneters.
`Hilton Head
`Island, SC.
`
`A, 62 ( 1997) 760-761.
`
`Biographies
`
`in 1965. He
`Stefcn Kwth was born in Stollberg, Germany,
`received the DipL-Ing. degree in 199 1 and the Dr.-Ing. degree
`in electronic engineering
`from
`the Technical University
`Chemnitz-Zwickau.
`Germany. in 1995. He iscurrentiy work-
`ing as a research assistant
`in the Department of Electronic
`Engineering and Information Technology at the same uni-
`versity, where he is engaged in research on micromechanical
`sensors and light-deflecting actuators.
`
`in 1953. He
`Rnr~n Halm was born in Chemnitz. Germany,
`received the Dipl.-Ing. degree in electrical engineering frotn
`the Technical University Karl-Marx-Stadt
`(Chemnitz)
`in
`1978. Currently. he is working as an assistant
`in the Depart-
`ment of Electronic Engineering and Information Technology
`at this university and is involved
`in development and manu-
`facture of’ micromechanical actuators.
`
`Christim
`in
`was born in Erlabrunn, Germany,
`Kn1&tnn
`1954. He received the DipL-Ing. degree in 1979 and the Dr.-
`Ing. degree in Electronic Engineering
`from
`the Technical
`University Karl-Marx-Stadt
`(Chemnitz)
`in 1985. His current
`work
`is focused on advanced metallization
`technologies
`for
`microelectronics and technology development
`for microsys-
`terns mainly based on Si micromechanical sensors and and
`light-deflecting actuators.
`
`in 1969. He
`Kenrtrtz Kehr was born in Oelsnitz, Germany.
`received the DipI.-Ing. degree in electrical engineering from
`the Technical University Chemnitz-Zwickau
`in 1994. Cur-
`rently, he is working
`as an assistant
`in the Department of
`Electronic Engineering and Information Technology at this
`university and is involved
`in design and characterization of
`micromechanical actuators.
`
`in 1963;. He
`./CW Mrh,zer was born in Chemnitz, Germany,
`received
`the Dipl.-Ing. degree in electrical engineering
`in
`1990 and the Dr.-Ing. degree in 1991, both from the Technical
`University Chemnitz-Zwickau,
`Germany. He is currently a
`research assistant at the Department of Electronic Engineer-
`ing and Information Technology at the same university. His
`current research activities are the simulation and design of
`microstructures
`for sensor and actuator applications.
`
`(Chemnitz),
`I/& Wollmnrz~~ was born in Karl-Marx-Stadt
`Germany,
`in 1968. He received the DipI.-Ing. degree in elec-
`trical engineering
`from the Technical University Chemnitz-
`Zwickau
`in 1995. Currently, he is working as an assistant in
`the Department of Electronic Engineering and Information
`Technology at this university and is engaged in development
`and manufacture of micromechanical actuators.
`
`in 194 I. He
`Wolfi-rrm Diifcel was born in Erfurt, Germany,
`received the Dipl.-Ing. degree in electrical and precision engi-
`neering from the Technical University Dresden
`in 1966 and
`the Dr.-Ing. degree from theTechnical University Karl-Marx-
`Stadt ( Chemnitz)
`in 197 1. In 1973 he worked at the Energetic
`Institute
`in Moscow on the reliability of electromechanical
`systems. From 1974 to 1986 he worked
`in the field of periph-
`eral computer equipment. Since 1987 he h:ls been involved
`with the research and development of micromechanical com-
`ponents. Since 1993 he has been a professor of microsystem
`and precision engineering at the Technical University Chem-
`nits-Zwickau.
`His current work
`is focused on design and
`simulation of micromechanical structures and their applica-
`tion, especially in precision engineering.
`
`(Chemnitz),
`Thor~~s Gesstler was born in Karl-Marx-Stadt
`Germany.
`in 1954. He
`received
`the Dipl.-Phys.
`and
`Dr.rer.nat. degrees from the Technische Universitst Dresden,
`Germany,
`in 1979 and 1983, respectively. From 1983 to
`1990, he worked at the Technische Universitrt Karl-Marx-
`Stadt in cooperation with
`the semiconductor
`industry
`in pro-
`jects on metallization
`technologies
`for IC production. His
`research topics were at first in the field of ion implantation
`and silicide technology, and later he worked on CVD, espe-
`cially of tungsten for application in microelectronic devices.
`He received his second doctorate in technical sciences (habil-
`itation)
`from the Technische Universitit Karl-Marx-Stadt
`in
`1989. Since 1940 he has been working on micromechanics
`and microsystem
`technologies based on silicon.
`In 1990,
`he became director of the Centre of Microtechnologies
`at
`the Technische Universitat Chemnitz-Zwickau.
`He was
`appointed as a professor on 1 February, 1993. His major fields
`of research are currently advanced metallization technologies
`for microelectronics
`(copper metallization) and technology
`development
`for microsystems mainly based on Si micro-
`mechanical sensors and actuators. ProfessorGessnerhaspub-
`lished more than 100 papers in these fields and holds seven
`patents. He is an active member of the Electrochemical Soci-
`ety and the IEEE.
`
`Petitioner Ciena Corp. et al.
`Exhibit 1034-7
`
`