結合SSIL、磁線圈與微孔於MO近場光學讀取頭的製程研究

Abstract

本研究針對利用近場光學突破繞射極限的光儲存系統:近場光學磁光(Magneto-Optic；以下簡稱MO)讀取頭進行相關研究，利用微機電技術提出一整合製程。此MO讀取頭包含:(1) 空氣軸承(air bearing)；(2) 微電磁線圈；(3) 奈米微孔；(4) 超半球固態浸沒式透鏡(Supersphere Solid Immersion Lens；以下簡稱SSIL)。本研究所提出之新式製程可批次生產，與傳統方法比較，元件不需組裝利於微小化，可批次量產；大幅簡化生產流程。研究並針對SSIL提出一新式而簡易的製程。 對製作之MO讀取頭進行出光測試，利用本研究室以往提出之電鍍法製作微孔；孔徑可縮至340奈米，並可進一步縮小。量測穿過孔徑為500奈米之出光光點大小，量測到之光點大小約為750~800奈米，這是由於可供操作之設備僅可量測遠場光點，量測結果為略經發散過的光點。觀察利用新式製程製作之SSIL，與設計值作比較，尺寸上最大誤差值少於2.4%。SSIL此時折射率為1.66。而利用UV-LIGA技術製作微金屬線圈。並製作出金屬內連線供電流輸入。最後利用厚膜之熱固性光阻SU-8強化整個元件結構。

The research focuses on the optical data storage system by near field recording that can break through the diffraction limit. The MO (Magneto-Optic) pickup head is studied and fabricated by MEMS(MicroElectroMechanical System)technology. The MO pickup head combines (1) air bearing, (2) microcoils, (3) nano-aperture, (4) Supersphere Solid Immersion Lens (SSIL). The proposed process is a batch process and does not need assembly to achieve a MO pick up head combining SSIL, nano aperture, air bearing and magnetic coils for high-density data storage. And a new process is also proposed to fabricate the SSIL. The spot size is measured to verify the process is feasible. The nano-aperture about 340 nm is fabricated by the “electroplating method”. The Full Width Half Maximum (FWHM) spot size is about 750 nm to 800 nm after the focused incident light passing through the nano-aperture about 500 nm. This is due to the available measured equipment is far filed detection. The dimensions of the SSIL is observed and compared with the designed values, the maximum errors occur in dimensions is less than 2.4% and the refraction index of the SSIL is about 1.66 at this time. The microcoils and interconnection lines are fabricated by UV-LIGA technology. The SU-8 is chosen to strengthen the pickup head.