Experimental study of the effect of target composition and heat treatment on the Ag deposit on the adhesion of the surfaces used in microelectromechanical systems (MEMS)

Abstract

Adhesion force is one of the major factors in MEMS technology specifically during micro assembling via micro grippers. Regarding the light weight of MEMS devices, the contact force between MEMS devices and the microgripper surface causes distinct problems such as sticking the MEMS surface to the microgripper, so the assemble procedure can be affected and microparts not be placed in the right position. so decreasing adhesion force has a significant role in improving micron assembly. Accordingly, in the current research work, the effects of various coating materials, deposition, and annealing temperatures on the surface roughness of microgripper substrate and its morphology are experimentally investigated considering the DC sputtering magnetron method to decrease adhesion force between microgripper substrate and MEMS device. For this purpose, seventeen silicon surfaces were used of which sixteen of them coated and one is non-coated. Deposited substrates can be classified into four groups four of them are deposited with double layers using two kinds of coating materials including Ti/Ag, SiO2/Ag, Ti/Ag-Pd-Cu, and SiO2/Ag-Pd-Cu respectively. After sample deposition, the AFM method was used to measure, the topographic images, the surface roughness, and the adhesion force. Regarding the differences in layers and distinct temperatures, the height and shape of hillocks directly depend on deposition and preheating temperature ranges. So as the deposition and preheating temperature increase, more hillocks grow and the adhesion force is more consequently. to 373 K and 573 K. Additionally, these changes result in changes in adhesion force.