Hi Ramon,
I don't know which pictorials you are looking at, but there is a number of
ways to make microvias in non-glass reinforced dielectrics (like liquid
dielectrics, RCC, polyimide film and Thermount) using plasma or chemicals
(hot NaOH or KOH).  There is also photo-sensitive dielectrics.  When you
consider that the microvias in flex-circuits for inkjet cartridges are all
etched rather than laser drilled, there must be more etched microvias than
laser drilled ones in the world.  The IPC Standards 2315 and 2226 show
about  8 different ways of making small vias in dielectrics.  Glass is one
of those materials that is very difficult to dissolve, hence a lot of
dielectrics are not glass reinforced.

Happy Holden
Westwood Associates





"Dehoyos, Ramon" <[log in to unmask]>
12/17/2003 09:55 AM


        To:     "TechNet E-Mail Forum." <[log in to unmask]>, [log in to unmask]
        cc:
        Subject:        RE: [TN] sequential build up process


                 Happy:
                 The vias in the pictorials seemed to be etched instead of
drilled.
If that is the case, what kind of chemical etches glass and epoxy?
                 Regards,
                 Ramon

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