Hi Zhenfeng,

I have a similar structure as yours. The electrode is 1um  TiW/Au/TiW on
top of 3um BCB and 0.8um SiNx. It works well with Al wire bonding. You can
try Al wire.

The method Michael mentioned is a good solution. You can also use small
indium ball to attach the wire on the bonding pad.

Best,
Yongliang


On Mon, Jul 15, 2013 at 10:50 AM, Michael Martin <
michael.martin@themicrowerks.com> wrote:

> Hi Zhang Zhenfeng,
>    The best solution is to engineer the device so that your bond pads are
> not over the BCB.  There is poor ultrasonic energy transfer to such a soft
> material.  We ran into a similar problem with 3um thick layers of polyimide
> and solved it by opening windows through the polymer to the oxidized wafer
> below in the region of the bond pads only.  Otherwise we used silver epoxy
> for our electrical connections.
>
> Good luck!
>
>
> On Fri, Jul 12, 2013 at 9:32 PM, Zhang Zhenfeng  wrote:
>
> > We have a problem about gold wire Ball bonding process of BCB-Sio2-Gold
> > pad :
> >   (Bonding machine:Gold Wire Automatic ball bonding 130KHz;Wire diameter
> > 0.7mil
> >    Pad size 60um )
> >
> > We use BCB layer for our device to lower the capcitator.
> > The structure of layer is BCB 2um--SiO2 0.5um---Ti/Pt/Au 0.7um.
> >
> > But the SiO2 layer is always peeled off from BCB layer when gold wire
> >  bonding even we adjust many parameter.The SiO2 layer is broken at
> > the gold bump edge when we do pulling test or bonding process.
> > There are always some bad part even we use the best one set parameter.
> > And the parameters isn't stable for diffrent wafer.
> >
> > Do you have any advise? Thanks.
> >
> > Zhang Zhenfeng
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--
Yongliang Yang
Phone: +1 650 804 8206
E-mail: ylyangbestry@gmail.com
_______________________________________________
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