PtSi IRCCD器件用长焦距Si微透镜阵列的制作研究

为了改善PtSi IRCCD器件的红外响应特性,需要添加长焦距微透镜阵列进行焦平面集光,本文提出了一种新的方法—曲率补偿法用于长焦距微透镜阵列的制作.扫描电子显微镜(SEM)显示微透镜阵列为表面极为平缓的方底拱形阵列,表面探针测试结果显示用曲率补偿法制作的微透镜阵列表面光滑,单元重复性好,其焦距可达到685.51μm.微透镜阵列器件与PtSi IRCCD器件在红外显微镜下对准胶合,显著改善了IRCCD器件的光响应特性.

FABRICATION OF Si MICROLENSES ARRAY WITH LONG FOCAL DISTANCE FOR PTSi IRCCD DEVICE

128×128 element square-based arch refractive silicon microlensesarray (MLA)is fabricated by a new method,named curvature compensation method.The new method is proposed to increase focal length of refractive microlenses array by over three times.It is described as follows:in order to decrease curvature of MLA made by the conventional method including photolithography,melting and ion beam milling,several new layers of photoresist is covered on it.The photoresist coated on convex place will flow to the concave place under the action of gravity.At the meantime,suface tension will make the surface of photoresis keep arc.The collective action of the gravity and the surface tension make the surfce of photoresist turn to more gentle.Then MLA is heated and consolidated,so photoresist and Si underlay form a integer,finally milled again.At last,gentle surface of photoresist will tranfer into Si underlay.Scanning electron microscope (SEM) show that microlens are gently square-based arch array,and surface stylus measurement show that the refractive microlens array has very smooth surface and extremely uniform dimensions,and the focal length of the microlenses array is 658.51μm,much longer than 200μm.the longest focal length of the microlenses array of the same size fabricated by conventional method.Using the new method,the filling factor is promoted to nearly 100%.Last,The MLA device and IRCCD device are aligned under an IR microscope and coupled with a kind of infrared glue.The IR response characteristics of the hybrid device are improved greatly.