1. Novel Method of Surface Activation for Electroless Metal Plating Jon Englert 1, Amy Ng 2, and Anthony Muscat 3 1 Department of Chemistry and Biochemistry, 2 Department of Materials Science and Engineering, 3 Department of Chemical and Environmental Engineering, University of Arizona Arizona Space Grant Consortium, Tucson, Arizona April 17, 2010 1

2. Metal Plating Corrosion and Wear Resistance Physical Properties Conductivity Characteristics –Lam Research: Wire Production 2

3. Electroless Metal Plating Process: Deposit a thin chemical layer on an object that can catalyze the nucleation of metal on its surface –No electrical power required –Plating on nonconductive surfaces –Uniform plating on complex substrates 3

4. Surface Activation for Electroless Metal Plating Challenge: Saturated monolayer required for uniform plating Approach: A minosilane self assembled monolayer (SAM) on SiO 2 substrate to form a reactive amino-terminated surface 4 3-aminopropyltrimethoxysilane APTMS Tri-functional aminosilane SiO 2

5. Common Surface Activation Methods 5 Liquid: Exposure to aminosilane solution and extraction with solvents Dilute Liquid: Exposure to highly diluted aminosilane in solvents Atmospheric Vapor: Exposure to aminosilane at atmospheric vapor and extraction with solvents [1] Petri D.F.; Wenz G.; Shunk P.; Schimmel T. Langmuir 1999, 15, 4520-4523.

6. Common Surface Activation Methods 6

7. Vacuum Vapor Method Samples are placed in the vacuum vapor reactor and pumped down Pump valve is closed and samples are exposed to precursor vapor System is purged of precursor vapor and the sample is removed 7 Fast deposition with less thickness variation No precursor dilution required Can be combined with vacuum controlled etching and plating processes

8. APTMS Vacuum Vapor Exposure 8

9. Comparison of Activation Methods 9

10. APTMS Surface Characterization 10 Water contact angle on an amino- terminated surface is approximately 50 ⁰ -70 ⁰ 1 [1] Petri D.F.; Wenz G.; Shunk P.; Schimmel T. Langmuir 1999, 15, 4520-4523.

11. APTMS Exposure and Extraction Other Solvents Used: Acetone Isopropyl Alcohol Chloroform 11 One cycle is one exposure and one extraction

12. APTMS Surface Characterization Amino-terminated surface present throughout process suggesting polymerization 12

13. APTMS Surface Characterization S1 = 6 cycles of 10min APTMS Exposure / 10min Toluene Extraction S3 = 10min APTMS Exposure X-Ray Photoelectron Spectroscopy (XPS) Analysis 13

14. Current Work Atomic Force Microscopy (AFM) and Fourier Transform Infrared Spectroscopy (FTIR) of activated surfaces. Cobalt plating on activated surfaces Surface activation using APDES precursor 14 3-aminopropyldimethylethoxysilane APDES Mono-functionalized aminosilane

15. Thank You! 15

16. 16 Vacuum Vapor Reactor Schematic

17. APDES Vacuum Vapor Exposure 17