Hi
  We have been trying to prepare a pinhole free metal (gold or Aluminum)
film on glass substrate but I see pinholes after the metal depostion on
glass unevitably.
  The total thcikness is about 100 A. We have tried e beam sputter or
thermal evaporator (both at about 4-6 A per second), tried to clean the
glass substrate (either glass wafer, quartz wafer or merely clean glass
slides) by using nanostrip or Piranha.
  But unfortunately I can avoid the pinholes on metal film especially
after I did some e beam lithography, photolithography or etching on it.
  Can someone here kindly give me some intuitions? Many thanks.

  I suspect that the glass must always have some particulates or organics
on it. Or the deposition process or lithography process might introduce
some adverse effect on metal atoms's adhesion to the substrate.

              Best Wishes,

                              Xin Heng