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Al, Pt metal adhesion

2003

Hello,

I am a student in the Nanofabrication Manufacturing Technology program at Penn State University, and I am working on my liftoff lab report from an experiment today. The experiment involved the adhesion of Aluminum and the adhesion of Platinum to both a silicon substrate and a silicon substrate with 1200Å of silicon dioxide grown as the top layer. My question was which metal will have the better adhesion? From previous experiments it seemed as if the Al adhered best to the oxide layer because Al oxidizes and bonds better with the Si oxide, while the Pt did not adhere at all. Is the only reason that Platinum would not adhere to the wafer because Pt does not grow an oxide? In this experiment however the Al adhered the best to the silicon substrate, making a very clear feature pattern, which wasn't the case in the last experiment. Also in this experiment the Pt seemed to leave behind the metal pattern slightly on the oxide sample, why is this? What caused the pattern to remain at all?

Also was wondering what could be done to better the adhesion of a usually poorly adhesive metal? (Usually working with Si substrates and Si02 substrates.)

One last question is what makes a metal material a better adhesive material than another metal?

Bryan Kelly
Pennstate Nanofab - University Park, Pennsylvania, USA