Dear Zigurts Majumdar,

Borofloat and Pyrex should be the same. I do not understand the cracking.
Could be something wrong with that bath of glass? Is the glass very thin
compared to the silicon thickness? If you have the time try to bond at 350C,
which takes a bit longer than 450C, and slow down / controle the cooling
down process. The voltage is high, but I cannot think of a reason why that
causes the cracking. The load is modest, but if your surface are smooth you
can maybe reduce it further.

Good luck,

Ton van Helvoort
Cambridge


>From: Zigurts Majumdar 
>Reply-To: [email protected]
>To: [email protected]
>Subject: [mems-talk] borofloat -Si bonding
>Date: Thu, 26 Sep 2002 16:15:07 -0500 (CDT)
>
>
>Hi,
>       I've read a paper where borofloat glass was anodically bonded
>to an Si wafer with 1200 V at 450 C, I used 15N of force for
>total area of about 1/3 of a 3 inch wafer. The glass cracks, I tried 3
>times. Does anyone have any suggestions about a better protocol? I've
>assumed the CTE is the same as Pyrex, which is true for the average
>CTE from 20-300C, but I haven't seen the data at 450 C.
>
>Thanks,
>
>Ziggy
>
>********************
>(Ziggy) Zigurts K. Majumdar
>Department of Physics
>Laboratory for Fluorescence Dynamics
>University of Illinois at Urbana Champaign
>1110 West Green St.
>Urbana, IL 61801
>********************
>
>
>
>
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