Hi Mehmet,

Where did you order the previous Pyrex 7740 and how thick is it?

On Thu, Feb 26, 2009 at 12:48 PM, Mehmet Aykol wrote:

> I had the same problem. I am using Pyrex 7740 blend or at least the vendor
> claims so. I have checked the thermal expansion coeff. of Si and Pyrex and
> they are almost the same. I concluded that either the batch of Pyrex was
> bad
> (because bonding process was going fine with previous batches) or Pyrex
> wafer was thin and it couldn't take the stress after the sample cooled
> down. Although I am also curious if this can be avoided.
>
> Mehmet

--
Jingru