This thesis deals with the development of magnetic microsystems. Arrays of planar magnetic microcoils are designed and modeled, then built and characterized. The microtechnologies used and developped in the project allow both for their miniaturisation and collective fabrication. The fonction of thèse coils is to apply local magnetic forces in ordet to control the déformation of a flexible membrane. Thin polymeric membranes (dJameter 40 mm) are manufactured on AsGa substrates by spin-coating and chemical etching, then permanent magnets are glued onto them. The application is a defotmable mirror used in asttonomy to correct the wavettont of incoming light in télescopes. This type of mirror is more compact than those currently used, and offers potentially higher resolution. The device is designed using magnetic and mechanical modeling, and a prototype is built
