FABRICATION OF 3D MEMS ANTENNA ARRAY FOR INFRARED DETECTOR USING NOVEL UV-LITHOGRAPHY APPARATUS, PLASTIC MICRO MACHINING AND MICRO ASSEMBLY TECHNIQUE
J.Y.PARK,K.T.KIM,S.MOON and J.J.PAK
Korea Institute of Science and Technology, Microsystem Research Center, KR
Keywords: 3D MEMS ANTENNA, UV-LITHOGRAPHY,MESH STRUCTURE BONDING
This paper describes the novel UV-Lithography technique for fabrication of 3D feed horn mold structure array using implementation of mirror reflected parallel beam illuminator(MRPBI) system, fabrication of 3D feed horn MEMS antenna's plate using plastic micromachining(PMM) by polydimethylsiloxane(PDMS) and the 3D MEMS antenna array are assembled using novel 3D MEMS bonding technique by mesh structure bonding(MSB) method.
A 3D feed horn shape MEMS antenna has some attractive features for array application, which can be used to improve microbolometer performance and enhanced optical efficency of TFT-LCD or applications for every display devices. Since MEMS technology have been faced many difficulties to fabrication of 3D feed horn shape MEMS antenna array itself and have been limitation of MEMS process for 3D MEMS antenna array assembled with IR detector array.
The purpose of this paper is to propose a new fabrication method to realize a 3D feed horn shape MEMS antenna array and applications for fabrication of 3D MEMS structure using a mirror reflected parallel beam illuminator(MRPBI) system with an ultra-slow-rotated and inclined x-y-z stage. Conventional UV-Lithography apparatus many difficult to fabrication of high aspect ratio structure(HARS). That is reason for every UV-Lithography apparatus cannot exposure perfect parallel light. From a theoretical analysis, it requires a columnar illuminator over 6m height in order to make a parallel light but generally a laboratory height is not 6m. So essential idea of this research is to make long propagation light ray using reflective mirror and generating a parallel light in a small lab space. Also a novel method of UV-Lithography process was tried to make a 3D MEMS structure array by exposing the generated parallel light onto x-y-z stage inclined and rotating at an ultra-slow rate.
A high-aspect-ratio sidewalls (300μm, inclined 30 ) had been fabricated using SU-8 negative photoresist and over 100μm vertical sidewalls structure array using PMER negative photoresist. It can be demonstrate to feasibility of realize 3D feed horn shape MEMS antenna array fabrication and We can fabricate to feed horn structure mold array(sidewall angle of feed horn mold:15 ,20 ,25 ,30 ,35 ) using MRPBI system and 3D feed horn antenna's plate (thickness of 30~40μm) using polydimethylsiloxane(PDMS) by capillay filling with clamping techinque.
Micro assembly of 3D MEMS antenna array and IR detector array have many difficult to conventional MEMS bonding process. That is reason of IR detector array were 2.5μm floated onto substrate, therfore thickness of bonding material required under 2.5μm for optimaization of contact gap and all of IR detector array were bonded with 3D MEMS antenna at low temperature. Conventional MEMS bonding technique require of material thickness over 2.5μm for bonding and high temperature process. To overcome those limitations, the propose to novel 3D MEMS bonding technique which is mesh structure bonding (MSB) using microchannel. This MSB technique can be used to produce low temperature bonding, thickness control of bonding material and detail bonding at mesh structure.
NSTI Nanotech 2003 Conference Technical Program Abstract