| With the development of semiconductor industry,MEMS as an important part of it,has been paid more and more attention.Micro-electromechanical system（MEMS）has the characteristics of small device volume,rich product functions and wide application fields because of its integration of electrical,optical,chemical,mechanical,biological and other characteristics.As a large semiconductor consumer,China has an urgent demand for MEMS devices.The research and production of MEMS is of great significance to the economic development and the improvement of people’s living standards of China.In this paper,we study the characteristics of the MEMS process and the process integration and optimization method of LED module reflection cavity devices.Set up the the process flow of optical MEMS devices which base on silicon substrate.We transform the process equipment and reduce the quality defects in the manufacturing base on the 8-inch IC manufacturing line which has been existing.The main contents are as follows:1.The mechanism of silicon etching.The composition,concentration and reaction temperature of the etching solution were tested by using the anisotropic characteristics of silicon characteristics.The process route of the etching solution with 26.5%&80℃KOH is determined.Set up the process route of hard-mask,LPCVD and dry oxidation process were used to deposit Si3N4 and Si O2 hard-mask,the thickness is150nm+600/400nm on the frontside and backside.2.The material and thickness of metal layer and reflection layer,the process route of Al/Ti/Ni/Au,Ti/Ni/Au,Ti/Ag is defined to achieve the balance of conductivity and adhesion.The reaction mechanism of metal etching is analyzed and the process route of etching process is determined.By the method of by-layer etching,the metal graphic on the devices surface is realized,which provides the electrical and optical properties for the LED module.3.The influence of MEMS 3D structure on the lithography process is studied,and the technical route of spray coating is determined.By adjusting the photoresist thickness,exposure time,baking temperature and other parameters,a stable mask is provided for the etching process.The process CD is effectively controlled at the same time.4.Quality defects such as graphic damage,fragmentation and low reflectivity occurred during the mass production.By analyzing the formation mechanism and causes of defects,targeted solutions are preset and verified by experiments,so as to reduce or eliminate product defects and improve production yield. |
