An investigation on FR4 as a based material for Ti/Au and Cu/Au evaporated fabrication for DNA biosensor application

Abstract

Glass fabricated with Ti/Au is a common technique for DNA in biosensor application. However, the wet etching technique produced poor adhesion for the Ti/Au on the glass. FR4 had been investigated to be used as a based material in this research. Three types of thermal evaporated methods for metal fabrication are investigated; Ti/Au, oxidized Cu/Au, and non-oxidized Cu/Au. In this research, Ti and Cu acts as adhesion layer for Au. A 2 cm length, 1.2 cm width and 1.6 mm thickness of FR4 was used as a base material. The FR4 was cleaned sequentially with acetone and isopropanol then left to dry with nitrogen gas. RF sputtering method is used to deposit Ti whereas copper layer (Cu) remained as it is on the FR4. The Cu/FR4 is cleaned sequentially with acetone and isopropanol and dried with nitrogen. It is found that the adhesion of Ti is good and worked on the FR4 surface. However, a major problem arises when the Ti/Au layer is unsuccessfully removed during the wet etching process. The result shows that non-oxidized Cu/Au fabrication worked well on FR4 as well as during wet etching technique. Hence, it is concluded that FR4 can be used as an alternative based material for Au evaporation in biosensor application. The first section in your paper.