000032247 001__ 32247
000032247 005__ 20190509131920.0
000032247 0247_ $$2doi$$a10.5075/epfl-thesis-1770
000032247 02471 $$2nebis$$a1920125
000032247 037__ $$aTHESIS
000032247 041__ $$afre
000032247 088__ $$a1770
000032247 245__ $$aNouvelles technologies de microstructuration de type UV-LIGA et fabrication de composants micromécaniques
000032247 269__ $$a1998
000032247 260__ $$bEPFL$$c1998$$aLausanne
000032247 300__ $$a124
000032247 336__ $$aTheses
000032247 520__ $$aThis study presents two techniques of structuration of type UV-LIGA (Lithographie, Galvanisierung und Abformung) based on the use of two thick photoresists which are a dry film resist called Riston® from DuPont and the new SU-8 negative-working resist from IBM. The relating processes to the structuration of these photoresists and some applications are presented too. The minimal resolution of the Riston® films has been found to be 30 µm for lines and trenches, and 40 µm for isolated holes in a 50 µm-thick film. A technique for the structuration of multilevel superimposed cavities has been set up. The verticality of the sidewalls (85.5°deg. to 87.5°deg) has been measured on film thicknesses between 25 and 100 µm. The SU-8 process has been studied and is presented. Some optical and mechanical properties have been analysed. We have determined a coefficient of light attenuation of 5.18 [db/mm] at 365 nm, a coefficient of thermal expansion of 52 [ppm/°C] and a biaxial modulus of 5.18 GPa. The verticality of the walls depends on the exposure energy and has been found to be higher than 89°deg. Layers from 750 nm to 2 mm can be exposed in one time, which seems to be the state-of-the art for a UV-photoresist to our knowledge. A specific process for the electroforming in multi-level superimposed cavities has been developed. With an adequate dosage of a leveling agent (coumarin) in the electrolytic Watt bath of nickel, a change in the growth rate of the high and the low level of the mold has been demonstrated. This rate is harmonised to obtain a flat deposition on the top surface of the formed structure. The UV-LIGA techniques developed in this thesis have found applications in the field of the-micromechanics. A flexible gearwheel, whose teeth are bound to the center via three integrated spring, and a multilevel gear system are the main realizations obtained by electroforming. These two structures have been used in a mechanism with a special watch mechanism and in a microreducer based on an electrostatic rotary micromotor. We have experimented with success the plastic injection of a gear system having 1.4 mm in height and 3 mm in diameter. Its mold has been electroformed on a master in SU-8. Theses microparts have demonstrated their functionality and have been mounted in commercialy-available-low-cost watches. All the process step of the LIGA technique have been established. The main advantages of this fabrication method are a better control of the tolerances and an improvement of the rugosity (against the wire electrodischarge machining technology). This technique is also cheaper and easier to start than X-LIGA.
000032247 586__ $$aLausanne, 1998
000032247 700__ $$aLorenz, Hubert
000032247 720_2 $$aRenaud, Philippe$$edir.$$g107144$$0240219
000032247 8564_ $$uhttp://vpaa.epfl.ch/page14980.html$$zAward
000032247 8564_ $$uhttps://infoscience.epfl.ch/record/32247/files/EPFL_TH1770.pdf$$zTexte intégral / Full text$$s7823231$$yTexte intégral / Full text
000032247 909C0 $$xU10324$$0252064$$pLMIS4
000032247 909CO $$pSTI$$pDOI$$ooai:infoscience.tind.io:32247$$qDOI2$$qGLOBAL_SET$$pthesis
000032247 919__ $$aLMIS4
000032247 920__ $$b1998
000032247 970__ $$a1770/THESES
000032247 973__ $$sPUBLISHED$$aEPFL
000032247 980__ $$aTHESIS