Micro-etching technology of high aspect ratio frameworks for electronic devices

High aspect ratio glass frameworks for spacer applications in the vacuum el ectronic devices were fabricated by photolithography. The material for the framework was photoetchable glass which has good mechanical and electrical insulating properties. The photoetchable glass was exposed to ultraviolet l ight, with a wave length of 312 nm, through a chrome mask. After heat treat ment, the glass was etched in 10% hydrofluoric acid using ultrasonic agitat ion. The final dimensions of the glass framework were greatly dependent on the mask patterns and ultraviolet light exposure conditions. The framework surface was affected by the tilting of the glass surface with respect to th e ultraviolet light source during the exposure process. In this work, glass frameworks, having a surface step of about 300 mu m, were obtained by tilt ing 11 degrees. An aspect ratio of 30 was obtained using photoetchable glas s of 1000 mu m thickness. (C) 1999 Elsevier Science S.A. All rights reserve d.