Study On The Machining Of Micro-nano Optical Array Elements Of Indium Phosphide By The CELT

Micro electromechanical system(MEMS),from its arising in the 1980 s, has been constantly promoting the development of the manufacturing technology towards the miniaturization. The use of electrochemical machining method for fabricating micro/nano structures has extensively attracted people’s attention. Compared with the traditional micromachining technology, such as IC technology, electronic beam and ionic beam machining, electrochemical micromachining method has excellent characteristics such as high resolution, simple operation, wide using scope, low cost, stress-free and so on. Thus more and more researchers are paying attention on it for fabricating complex three-dimensional micro-structures.Indium phosphide, as the second generation of semiconductor material, is a very important photoelectric material. It is very significant for the micromachining of Indium phosphide. In this paper, CELT was studied to apply to fabricated 3D micromachining on the surface of the Indium phosphide wafer. Finally a 3D microlens array has been successfully transferred on to the surface of InP wafer by the PMMA/Ti/Pt microlens array mold with the resolution of submicron level. The main conclusions of this work are described as follows:1 、 By comparing investigation for Indium phosphide with the same kind compound semiconductors in chemical properties, combined with electrochemical measurement and corrosion weight-loss test, HNO3/HCl and Br2/HCl were selected as the etching systems. The corresponding scavengers were determined as NaOH and L-cystine respectively by analysis the cycle volt-ampere characteristic curve.2 、Standard Pt micro cylindrical electrode was used to investigate the duplication processing effect for the two etching systems respectively. The etching system and process parameters were optimized. Br2/HCl/L-crystine system was finally selected as effective etching system. The best etching processing resolution can be got When the ratio of L-cystine and NaBr is 3:1 Through the duplication processing research and CV curve analysis. And the etching processing resolution of the Br2/HCl/L-crystine system was preliminary determined.3 、Micromachining research for micro-optical lens array on p-InP surface was done by using CELT. Ultimately, a large area of micro-optical concave lens array had been obtained on the surface of n-InP. For the micro-optical convex lens mode which was 102.91 μm in diameter and 10.757 μm in height, the machining precision along the height was about 0.99 μm and its relative error was about 0.9%.The machining precision along the radius was about 0.44 μm and its relative error was about 4.1%. The experiments showed that submicron resolution could be achieved on the surface of InP by CELT duplicating processing for micro-optical elements. It shows that CELT is a promising method for fabricating complex three-dimensional micro-structures for micro optical use.