`
`ELSEVIER
`
`Sensors and Actuators A 66 ( 1998) 76—82
`
`
`
`SEN§m0RS
`ACTUATORS
`APHYSICAL
`_______:
`
`Silicon mirrors and micromirror arrays for spatial laser beam modulation
`
`Steffen Kurth *, Ramon Hahn. Christian Kaufmann. Kersten Kehr, Jan Mehner, Udo Wollmann,
`
`Wolfram Dotzel, Thomas Gessner
`Technical University Chetitriitz-Zwir‘kau. Department ofEtectriml Engineering and Information Technology, 0-09107 Citt’lltltf11. Gemmtz)‘
`
`Received 7 October 1997: accepted 18 November 1997
`
`
`
`A bstract
`
`This contribution deals with the design, technology and experimental investigations of mirrors and micromirror arrays made of mono-
`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 BESOl 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
`field of micromechanics. Furthermore. results of application—related experiments oflaser projection are given. © 1998 Elsevier Science SA.
`All rights reserved.
`
`Keywords: Micromirror arrays; Two-directional deflection; Modified BESOl 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 pm. 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
`
`* Corresponding author. Tel: + 49 371 531 32. 20; fax: +49 371 531 32
`59.
`
`0924-4247/98KS19100 © l998 Elsevier Science SA. All rights reserved.
`PHSO924»4247(97)01731—7
`
`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. Principle of operation
`
`The bulk-micromachined KOH-etched mirrors and mirror
`
`arrays (Fig. 2) consist of 30 pm 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 um X 3000 um with
`an electrode gap of 370 am.
`The 5 pm thick mirror plates and elastic beams of the
`micromirror arrays in modified BESOI technology (Fig. 3)
`contain a reflecting part on each mirror 50 umX 250 pm in
`size. The size of the elecrrode 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 celli The first mode shape is the rotation of the
`
`Petitioner Ciena Corp. et al.
`
`Exhibit 1034-1
`
`

`

`S. Kurtli at (1/. / Sensors and Actuators A 66 (1998) 76—82
`
`77
`
`A
`
`1 Tilting angle (equal voltage)
`2 Torsional frequency
`3 Driving voltage (equal tilting angle)
`4 Translatowdeflection
`
`the movement in further degrees of freedom is often very
`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:
`
`
`10:5 C,0%:Zkr0a
`
`82w +
`8w +
`O m M
`CI 3;
`
`0
`
`A} w
`
`0
`
`1th
`
`er. —er3
`
`171
`
`=
`
`”’32
`
`ell
`
`812
`
`U:
`
`(i)
`
`
`
` Normalizedcharacteristics
`
`0.001
`
`1.0
`
`0.1
`0.01
`Dimensional scale factor
`Fig. l. The influence ofdimensions on mirror properties.
`
`with the mass moment of inertia J. the mass m. the damping
`coefficients Cr and ct, the electrostatic coupling coefficients
`moving plate. The electrical force produces an additional. in
`eri and e”. the bias voltages um and the driving voltages 17,-.
`some cases undesired, trnnslatory deflection of the mirror,
`The natural frequencies without damping are nearly given by
`which is directed to the driving electrodes. The amplitude of
`
`26M! 80 iii“
`12.93:
`
`é-NQM F 693%?
`XIJK
`Ili'.’ Si! Mn
`3 38¢}! 9’ {fill
`.—._.L‘__.
`
`2--
`
`{In
`
`
`
`
`Distance wafer
`
`Actuator wafer
`
`Glass bottom water
`
`Isolation layer stack and driving electrodes
`Fig. 2. SEM photograph of the back of a two-directional mirror and of a mirror array in bulk micromcchanics and cross»sectional schematic view.
`
`1.. 33";Eefifl“ .
`
`Mirror strip
`
`— Torsion beam
`
`
`
`Supporting post
`
`
`Thermal oxide
`
`Back-thinned
`silicon layer
`Sacrificiai layer
`Etch stop layer
`CVD oxide
`
`Driving electrodes
`
`Supponi no post
`Carrier
`Fig, 3, SEM photographs and cross-sectional schematic view of a minor array in modified BESOI technology.
`
`Petitioner Ciena Corp. et al.
`
`Exhibit 1034-2
`
`

`

`78
`
`S. Kama er al. / Sensors and Actuators A 66 (1998) 76-82
`
`Displacement w
`
`Mirror plate
`
`
`
`
`
`Torsion beam
`
`
`Fig. 4. Schematic of the cross section and working principle of a single cell.
`
`Driving electrodes
`
`i 24 Gml‘
`.=' —
`,
`\1/ Iblilll‘yl‘i‘ithpb‘l
`w”:
`for rotary motion and
`
`_
`
`24 E1
`.1, [lilmwmfhpSi
`
`wn‘
`
`2
`
`)
`
`(
`
`(3)
`
`for translatory motion without any electrostatic field. where
`the shear modulus is Gm. the torsion moment is It, 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 pg.
`The electric field ofthe applied bias voltage causes adisplace—
`them-depending torque and decreases the elasticity k of the
`spring~mass oscillators to
`
`dlcg
`k1.*=kr— ,da' 2
`
`(4)
`
`The natural frequency is decreased as well. The coefficients
`for electrostatic translating force and rotating torque can be
`expressed by
`
`.
`
`E‘an-ilm
`_
`e” ‘4d[ot-m/'2)a+d]
`6w I
`1 4 :
`m l7}
`C“ 4d[—(wm/2)a+d]
`—fl[it—~——d+(—”V”‘/‘U
`ell—2
`a3ntwm/2)a+d
`(Wm/2)a2+da
`
`9 _61m[ l1n
`d
`‘
`’
`it’m/Z
`r3
`2
`or: —(wm/2)a+dl((tt‘m/Z)oz3—da
`respectively, with the tilt angle aiO and the electrode gap
`(1.
`
`(58.)
`
`5})
`
`(
`)
`(6a)
`
`(6b)
`
`)]
`
`The damping coefficients cI and c,., the stiffnesses kl and
`kr. the driving force Fel and the driving torque MCI 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. tow. the surrounding
`gas additionally acts as a spring (oFV> O) or as an inertial
`mass (chV < 0).
`Most ofthe mechanical energy dissipates in the viscose air
`film within the electrode gap. lfd << [whim and ifthe working
`frequency is less then a critical frequency toC = 713' {MW 1217‘.”
`
`(l/wn',2 + 1/11,?) [7] . where 1m and wm are lateral plate dimen—
`sions, p is the ambient pressure. 77;.“ is the effective viscosity
`[8] and (1 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:
`
`
`
`itiuia—
`
`127),)“ Bx‘
`
`1)
`
`cy- p 7
`
`(it
`
`,
`
`d
`
`If the working frequencies are below the critical frequency
`LUC, the time-dependent term of Eq, (7) can be neglected and
`we get a Poisson equation. which can be readily solved for
`simple geometries [7].
`Calculated results are:
`.
`’
`’5
`
`c..=@.~D=l—w=K,.n“Tlm
`Ct
`at
`d"
`3
`
`C1=FD_JP -dA=K-‘nuri:1m
`it
`li’
`1
`
`(9)
`
`(8)
`
`where A is the plate area. [Q and l’t’r depend on the aspect ratio
`lm/wm (K5043 [9] and Kr=17.6-l><10‘3 for square
`plates).
`If the working frequencies are above we. an analogy of
`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 case 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 flow. 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.
`Electrostatically cxcitcc' mirror
`
`Adjacent mirror cell without
`electrostatic torque
`
`
`
`Suspending grid
`Flurd vaccity
`Fig. 5. Velocity plot of the fluid flow around a micromirror array using
`FLOTRAN.
`
`Petitioner Ciena Corp. et al.
`
`Exhibit 1034-3
`
`

`

`S, Kurt/t 4‘! al. /Se‘n$0rs and Actuators A 66 (1998) 76—82
`
`79
`
`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
`
`3.]. Conventional bulk silicon mirrors and mirror army
`
`The actuator design comprises four different wafers, aglass
`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 4 inch silicon wafers.
`The silicon membranes situated in the actuator wafer and the
`
`frames between them are patterned by anisotropic etching
`with KOH using 8102 and Si3N.1 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 0n the
`mirror front side and as a conducting and stress compensation
`layer on the mirror back side. Fabricating the glass carrier, a
`150nm Si3N.L 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 am aluminium), which are
`prepared on top of the nitride. Above these electrodes. a layer
`stack consisting of PECVD SigN_h PECVD SiOZ and PECVD
`Si3N4 insulates the structure against the air, since during the
`actuator operation a relatively high voltage is applied. The
`actuator wafer is attached to the glass carrier wafer by anodic
`bonding.
`
`3.2. Mirror army in modified BESOI technology
`
`Following a thermal oxidation and a deposition of CVD
`oxide, the driving electrodes are applied on and patterned on
`the carrier water. A further CVD oxide, deposited on this
`wafer and on an additional blank active wafer. serves as
`
`Excttatlon
`Signal
`
`
`Sig nat-
` Qopplen
`
`Analyser
`interferometer
`
`
`
`
`
`
`.» (i Mirrorcells
`
`7 (30 pm St)
`
`Suspending grid
`{250 pm Si)
`
`_
`Glass earner
`
`~17
`Electrodes (tum All
`Fig. 6. Measurement set-up for the frequency response.
`
`sacrificial layer and silicon fusion bondable surface. Before
`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 um 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 plasma etching
`and released by wet etching of the sacrificial oxide.
`
`4. Characteristics
`
`4.]. Behaviour measurement
`
`Measurement of the frequency transfer functions leads to
`some characteristic values: natural frequencies and damping.
`eigenfrequencies, dc. transfer rates and transfer rates at a
`frequency near the natural frequencies. A Doppler interfe—
`rometer detects the rotation concerning the ,r- 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 l.
`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 dc. voltage. It has been
`
`
`
`
`----- 1 »- »~~— -— -~-
`
`
`
`
`
`““\
`W ,
`
`4-06
`300
`2.0
`1.5
`Frequency [kHz]
`Frequency [kHz]
`Fig. 7. Natural frequencies and mode shapes of an array in bulk micromechanics ( le t) ; frequency response function of an array in modified BESOI technology
`tright).
`
`500
`
`665
`
`Petitioner Ciena Corp. et al.
`
`Exhibit 1034-4
`
`ranslation in z-direction 1.-
`
`
`
`
`
`
`
`
`
`
`1:0
`
`2.5
`
`3.0
`
`100
`
`200
`
`

`

`80
`
`Table 1
`
`St Kztrrli et all /Sensorr and Actuators A 66 (1998) 76—82
`
`(eg, 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.
`[ 10] ) . In this way. an immediate evaluation of the calculated
`damping and fluid—caused coupling becomes possible.
`Results are shown in Fig. 8.
`
`5. Experimental
`
`5. 1. Driving at resonance frequency
`
`A relatively large mechanical tilting angle of up to l0° 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 of the 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. C[Used-loop control
`
`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
`
`
`
`Fig. 10. Photograph of the screen with symbols projected by the pattern
`scanning laser projection system,
`
`
`
`Torque[Nm] [0 E AOO
`
`filting angle [radi
`
`0.02
`
`0.04
`
`Fig. l l. Dependency of the static characteristic and natural frequency ofthe
`resonator.
`
`Petitioner Ciena Corp. et al.
`
`Exhibit 1034-5
`
`Results of an experimental modal analysis. natural frequencies and mode
`shapes
`Amy in sun :Itrcromachmg Array n! maxlifled Besotmhnuingy
`
`Nammi frequenc)
`Meat- shape
`Natural lrequcrcy
`Med: slaps:
`{Htl
`,Htl
`
`.
`240m]
`use. 1010
`in mode
`is; mod.-
`Rotation oi the
`2 Rotaiiun arm:
`mirror plates
`concerning me
`concerning the
`mitt
`,x-ams
`2300
`End mode
`th‘lalltm at the
`
`m nor plates
`
`
`
`mesh grating
`
`observed hat the error of tilt is less than 0003‘” according to
`the tilt before switching the driving voltage and before driving
`at the resonance frequency.
`
`4.2. Model evaluation
`
`One of the goals of the experimental characterization of
`minors 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
`(cg,
`the mass
`moments of inertia) and, of course, more discrepant values
`0.001
`
`
`
`Excited cell
`
`(10001
`
`0.00001
`
`iHliwll
`
`
`
`Adjacent.
`nonexcited cell
`
`
`
`
`1~101000
`
`1050
`
`1100
`Frequency [Hz]
`Fig. 8. Frequency response functions of an excited and an adjacent non-
`cxcitcd array cell. simulation data compared to the data olan experimentally
`enhanced model and measured data points.
`
`1150
`
`1200
`
`
`
`Spherical mirror
`/
`
`/ //N \\ V // /Laserbeami ii
`
`\
`‘i—‘—i‘>
`//
`
`Time 20 ms
`
`
`
`
`
`
`
`
`Time
`
`
`
`,
`
`
`
`ZD—mirror
`
`Electrodes
`
`o>
`
`Screen
`
`Laser diode
`
`Fig. 9. Experimental set—up for pattern-scanning laser projection.
`
`
`
`2m. 2852
`3rd mode
`Translation of the
`aural plates in
`l-direflmr‘
`
`

`

`S. Kurt/i er til. /Sen.mrs rim] Actuators A 66 (1998) 76—82
`
`81
`
`11
`
`Laser
`
`Position sensitive device
`
`9:
`
`
`ControllerwithDSP
`
`
`
`Normdeflection
`
`5001*
`
`8. _S
`72a, 0E>
`
`50-0
`
`
`0
`10
`20
`Timetmst
`Fig. 12. Experimental set-up ofthe closed-loop system with detection of the position at one mirror cell and driving of all cells.
`
`properties. but even more strongly by an unstable working
`point caused by the electrostatic field. It is necessary to satisfy
`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 ofthe 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 thatthe resulting
`scan is very sensitive to the controller parameters. It is useful
`to adjust the parameters empirically following the initial pre-
`dicting procedure.
`
`with an error of less then 0.003° becomes possible with the
`presented technological approach using monocryStalline sil-
`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 fluid—
`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 ofthe 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 authors would like to acknowledge the support by the
`DFG (Deutsche Forschungsgemeinschaft), Sondeifor-
`schungsbereich 379. and the Federal Ministry for Education
`and Research (contract l6SV397/8).
`
`References
`
`6. Conclusions
`
`Scaling down the dimensions is a promising way to enlarge
`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-
`logue operation. High reproducibility of the scanning position
`
`timely
`light processing and MEMS:
`[l] LJ. Hornbeck. Digital
`convergence for a bright future,
`in Micromachining and Micro-
`t‘abrication '95. SPIE Thermatic Applied Science and Engineering
`Series. Austin, TX. Oct. 1995.
`Infrared
`[2] A. Wagner. K. Reimer. A. Maciossek, U. Hofmann,
`micromirror array with large pixel size and large deflection angle, Tech,
`Digest. 9th Int. Conf. SolidAState Sensors and Actuators (Transducers
`‘97), Chicago, IL, USA, 16—19June. 1997. vol. l.pp. 75—78.
`[3] M. Fischer, M. Niigerle. D. Eichner, C. Schollhorn. R. Strobel, Sensors
`and Actuators A. 52 l 1996) 140444.
`
`Petitioner Ciena Corp. et al.
`
`Exhibit 1034-6
`
`

`

`82
`
`S. Karin er u]. /Sensor5 (mdActmrm/‘JA 66 (1998) 76—82
`
`[41 MB. Kiting. D.A. Francis. CJ. Chang-Hasnain. O. Solgard. KY. Lau.
`R. Muller. Actuated polysilicon micromirrors for raster-scanning
`displays. Tech. Digest.9th Int. Cont". Solid-State Sensors and Actuators
`{Transducers ‘97). Chicago. IL. USA,
`[6—19 June. 1997. vol. 1. pp,
`323—326.
`[5 P. Hsiang. A. Garcia-Vaienzula, MA. Neifeld. M. Tabib-Azar,
`Micromachined 50 um><250 pm silicon torsional mirror arrays for
`optical
`signal processing. SPIE Proc..
`Integrated Optics
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`
`
`Biographies
`
`Steffen Kurt/t was born in Stollberg. Germany. in 1965. He
`received the Dipl.—Ing. degree in 1991 and the Dr.-Ing. degree
`in electronic engineering from the Technical University
`Chemnitz-Zwickau. Germany. in 1995. He is currently 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.
`
`Ramon Hahn was born in Chemnitz. Germany. in 1953. He
`received the Dipl.-1ng. degree in electrical engineering from
`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.
`
`in
`Christian Kzrttfitmnn was born in Erlabrunn. Germany.
`1954. He received the Dip1.-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-
`tems mainly based on Si micromechanical sensors and and
`light—deflecting actuators.
`
`Kersten Kehr was born in Oelsnitz. Germany. in 1969. He
`received the Dipl.—Ing. degree in electrical engineering from
`the Technical University Chemnitz-Zwickau in 1994. Cur-
`rently. he is working as an assisrant in the Department of
`Electronic Engineering and Information Technology at this
`university and is involved in design and characterization of
`micromechanical actuators.
`
`Jan Melmer was born in Chemnitz. Germany. in 1964. He
`received the Dipl.-lng. degree in electrical engineering in
`1990 and the Dr.-Ing. degree in 1994. 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.
`
`Udo Wollmami was born in Karl—Marx—Stadt (Chemnitz).
`Germany, in 1968. He received the Dipl.—lng. 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.
`
`Wolfram Dotzcl was born in Erfurt. Germany. in 1941. He
`received the Dipl.-Ing. degree in electrical and precision engi«
`neer‘ing from the Technical University Dresden in 1966 and
`the Dr.—lng. degree from the Technical University Karl—Marx—
`
`Stadt ( Chemnitz) in 197 1. In 1973 he worked atthe 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 has been involved
`with the research and development of micromcchanical com-
`ponents. Since 1993 he has been a professor of microsystem
`and precision engineering at the Technical University Chem—
`nitz—Zwickau. His current work is focused on design and
`simulation of micromechanical structures and their applica—
`tion. especially in precision engineering.
`
`Thomas Garner was born in Karl—Marx—Stadt (Chemnitz).
`Germany.
`in
`1954. He
`received the Dipl.-Phys.
`and
`Dr.rer.nat. degrees front the Technische Universitiit Dresden.
`Germany.
`in 1979 and 1983. respectively. From 1983 to
`1990. he worked at the Technische Universitat 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 (liabil-
`itation) from the Technische Universitiit Karl-MarX-Stadt in
`1989, Since 1990 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. Professor Gessnerhas pub—
`lished more than 100 papers in these fields and holds seven
`parents. He is an active member of the Electrochemical Soci—
`ety and the IEEE.
`
`Petitioner Ciena Corp. et al.
`
`Exhibit 1034-7
`
`