Hello,

            This is the side wall polymer, which get more thicker and might
be due to microscope light sccatering giving you yellow colour.  it happen
because of the passivation time is comparative large of the etch cycle.
what you can do please keep the passivation time about half of the etch time
cycle. moreover you can clean the polymer by giving your sample a rigrious
RCA1 cleaning or EKC cleaning.


Best wishes,

Manish Hooda
----- Original Message -----
From: "Julie Verstraeten" 
To: "General MEMS discussion" 
Sent: Thursday, February 23, 2006 4:32 AM
Subject: [mems-talk] Yellow "film" after DRIE ???


>
> Hi,
>
>
> I recently deep etched two Si samples. I used the same recipe as before
exepted
> for one parameter. After etching, the silicon surface (not the photoresist
> mask...) was covered with a powder-like yellow film. I don't understand
why.
>
> For the firt sample, the coil power was raised to 700W (instead of 600)
during
> passivation
>
> and for the second sample, the platen (electrods) power was decreased to
10W
> (instead of 12) during etching.
>
>
> The idea was to reach more vertical walls. I know the coil power has an
effect
> on the passivation film thickness. The platen power drives the ionic
> bombardment.
>
>
> The etching and passivation times were 7.8sec and 7sec respectively. I
don't
> know if this film could come from the passivation film or from any kind of
> contamination.
>
> Does anybody has some idea about that?
>
> Thank you,
>
> Julie
>
>
>
>

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