Au contaminated DRIE process for Si / Drilling Holes in Pyrex Wafers

Sebastian J. Osterfeld sjo at
Mon Oct 30 17:06:42 PST 2006

The SNF should soon have a "contaminated" XeF2 etcher online, which will 
do Si-DRIE, but only isotropic. Then there is also the possibility of 
using Drytek, but just like the XeF2 it is either isotropic, or quite 
slow, and possibly both - you'd probably have to etch several days on 
one wafer to get an anisotropic etch. If you are interested in isotropic 
etches, you can ask me again, or talk to Ed Myers.

On a related note, I also was interested in how to drill (DRIE-ll) holes 
into Pyrex wafers. Mechanical drilling causes unacceptable damage to the 
existing microstructures, and so I inquiried about alternatives such as 
masked sand blasting, laser drilling, water drilling, etc. I'll post the 
responses I got from SNF members below.

~ Sebastian Osterfeld

> Dear SNF Lab users,
> I am considering drilling holes into a 4" Pyrex or glass wafer. Last 
> time I checked, doing this in-house wasn't quite feasible, due to both 
> the large number of holes I need and due to the fact that mechanical 
> drilling with the microdrill press easily causes unacceptable 
> delamination damage to the existing microstructures due to the 
> vibration. What other places can you recommend to have this done?
> Ideally, the place would:
> - Have a fast turnaround time
> - Do single 4" wafers at reasonable cost
> - Accept some kind of layout file for this job
> As far as the holes are concerned, I'd go with whatever is available, 
> but ideally:
> - They'd be around 800 microns in diameter
> - They'd be flush with the surface within 50 microns (i.e. limited 
> laser rim formation)
> Thanks!


in the event that you would like to try yourself, back when I was in 
school, I would drill 1.5mm holes on pyrex and borofloat with the 
following precautions:

- Air turbine mounted on a mill/drill (you need very high rpm)
- Glass Chip clamped very tight (to kill vibrations that would shutter 
the chip)
- Fully submerged in a water bath (for both cooling and avoiding glass 
- Mini mill-bits from McMaster were good enough.

Good luck!

************************************************************************* <>

Santa Cruz, CA

They can handle all sorts of glass and crystalline wafer fabrication, 
polishing, and machining task with excellent quality.

James Conway
CIS 31 8:30 - 9:30 AM daily

Hi, Sebastian,

I think you make check Mary Tang for drilling holes. There is a small 
drill machine next to wafersaw.


Hi Sebastian,

Have you tried American Precision Dicing? They have a BioTech Service 
Division where they use abrasive drilling to make holes for fluidic 
chips. They are located in San Jose.  Here is the link:

Hope this helps.

Best regards,

Hi Sebastian,

American Precision Dicing in San Jose can grit blast holes of that size into



    Try Applied Laser Solutions in Union City/Fremont. Very reasonable
prices. YOu can google their phone # on the web.



Dear Sebastian,
    Mary Tang will probably write back to you with this information, but in
case she doesn't, you should go talk to her.  In the wafersaw room there is
a high-speed micro-drill press.  It works with "tripple ripple" diamond
drill bits.  I've used it to drill many holes in glass (Corning 7740) and
fused silica wafers, always with good results.  Mary can show you how to
use it.
    Hope this helps!



Talk to Chris at Precision microfab.

Try this link.  They can do what you are looking for.


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