Development of an alternating magnetic-field-assisted finishing process for microelectromechanical systems micropore x-ray optics.

X-ray astronomy research is often limited by the size, weight, complexity, and cost of functioning x-ray optics. Micropore optics promises an economical alternative to traditional (e.g., glass or foil) x-ray optics; however, many manufacturing difficulties prevent micropore optics from being a viable solution. Ezoe et al. introduced microelectromechanical systems (MEMS) micropore optics having curvilinear micropores in 2008. Made by either deep reactive ion etching or x-ray lithography, electroforming, and molding (LIGA), MEMS micropore optics suffer from high micropore sidewall roughness (10-30nmrms) which, by current standards, cannot be improved. In this research, a new alternating magnetic-field-assisted finishing process was developed using a mixture of ferrofluid and microscale abrasive slurry. A machine was built, and a set of working process parameters including alternating frequency, abrasive size, and polishing time was selected. A polishing experiment on a LIGA-fabricated MEMS micropore optic was performed, and a change in micropore sidewall roughness of 9.3+/-2.5nmrms to 5.7+/-0.7nmrms was measured. An improvement in x-ray reflectance was also seen. This research shows the feasibility and confirms the effects of this new polishing process on MEMS micropore optics.

[1]  Yoshiharu Namba,et al.  Ultra-precision polishing of electroless nickel molding dies for shorter wavelength applications , 2008 .

[2]  Y. Mori,et al.  Figuring with subnanometer-level accuracy by numerically controlled elastic emission machining , 2002 .

[3]  E. Spiller.  Smoothing of multilayer x‐ray mirrors by ion polishing , 1989 .

[4]  Stefan Kraft,et al.  Status of x-ray optics development for the XEUS Mission , 2004, SPIE Astronomical Telescopes + Instrumentation.

[5]  Han-Ming Chow,et al.  Micro-hole machining using micro-EDM combined with electropolishing , 2006 .

[6]  Manabu Ishida,et al.  Development of high-resolution and light-weight x-ray optics with deformed silicon wafers , 2009, Optics + Optoelectronics.

[7]  B. Yan,et al.  Use of micro ultrasonic vibration lapping to enhance the precision of microholes drilled by micro electro-discharge machining , 2002 .

[8]  R. Maeda,et al.  Evaluation of the soft x-ray reflectivity of micropore optics using anisotropic wet etching of silicon wafers. , 2010, Applied optics.

[9]  Raul E. Riveros,et al.  Ultra light-weight and high-resolution X-ray mirrors using DRIE and X-ray LIGA techniques for space X-ray telescopes , 2010 .

[10]  Yoshitaka Ishisaki,et al.  Micropore x-ray optics using anisotropic wet etching of (110) silicon wafers. , 2006, Applied optics.

[11]  M. Gretillat,et al.  Vertical mirrors fabricated by deep reactive ion etching for fiber-optic switching applications , 1997 .

[12]  J. Svoboda,et al.  Magnetic techniques for the treatment of materials , 2004 .

[13]  R. Petre,et al.  Mirror technology development for the International X-ray Observatory mission , 2009, Optical Engineering + Applications.

[14]  Raul E. Riveros,et al.  Magnetic field assisted finishing of ultra-lightweight and high-resolution MEMS x-ray micro-pore optics , 2009, Optics + Optoelectronics.

[15]  Holger Becker,et al.  Hot embossing as a method for the fabrication of polymer high aspect ratio structures , 2000 .

[16]  P. Bomans,et al.  Direct observation of dipolar chains in iron ferrofluids by cryogenic electron microscopy , 2003, Nature materials.

[17]  Keith A. Nugent,et al.  On the concentration, focusing, and collimation of x‐rays and neutrons using microchannel plates and configurations of holes , 1989 .

[18]  Marcos Bavdaz,et al.  X-ray focusing with Wolter microchannel plate optics , 2002 .

[19]  L. Speybroeck.  AXAF Mirror Fabrication , 1994 .

[20]  Raul E. Riveros,et al.  Novel ultra-lightweight and High-resolution MEMS X-ray optics for space astronomy , 2009, 2011 16th International Solid-State Sensors, Actuators and Microsystems Conference.