Hi, Andy,

My structures are pretty big, so the profile requirement is vitually not a
constraints (CD > 5 µm and film thickness of both SiN and SiO are < 600 nm
that is also the depth to be etched, again, don't worry about the
selectivity.  Resist > 3 µm thick).  Anisotropy is not very important either
for the same reason.  Basically I just need something works that could give me
a satisfactory etch rate to avoid the burning and baking of resist too much.
The substrate would be cooled by He backing which should be efficient I
guess.  I haven't contacted the vendor yet but will do so in a moment.  Thank
you for your time.

Lihuan

Andy McQuarrie wrote:

> Hi Lihuan,
>
> Both SiO2 and Si3N4 can be etched with SF6 as the F source. However,
> it's impractical to suggest starting conditions without knowing additional
> constraints such as degree of anisotropy, profile requirements, etc.
> - Nominally, SiN will etch in low ion energy regimes whereas SiO requires
> higher ion energies - however, this also tends to be reflected in the etch
> profile seen in F plasmas without passivation components (SiN often
> will be isotropicly etched).
>
> Therefore additional information that would help would be:
>
> - Profile and CD requirements
> - Film thicknesses (SiN, SiO and resist)
> - Whether substrates are actively cooled (or whether you're using small
> parts of a wafer on a carrier).
>
> Apologies for answering a question with a question (a few questions that
> is)
> but this will help in answering you. On a practical front, have you
> contacted
> the vendor?
>
> Good luck, Andy
>
> Message text written by General MEMS discussion
> >
> Dear experts,
>
> We only have the following gases available in our Oxford plasma lab ICP
> etching system, SiCl4, Cl2, CH4, H2, SF6, O2, Ar and N2.  I want to etch
> both SiO2 and Si3N4 (seperately, selectivey not needed, layers were CVD
> grown on III-V, say GaAs substrates) with a acceptable etch rate, say
> >50nm/min (preferably >100nm/min).  I prefer to use resist as mask.  Can
> anybody give me a receipe such that I have something to start
> optimzation with?  Thanks a lot.
>
> Best regards,
>
> Lihuan
>
> --
> Lihuan Song
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--
Lihuan Song
Opto-Electronics Group (OE)
Advanced Components and Sensor Systems department(ACSS)
Microsystems, Components and Packaging Division (MCP)
Interuniversity MicroElectronics Center (IMEC)
======================================================
Lihuan Song              Tel: +32-16-288-066 (Office)
MCP/ACSS/OE               Fax: +32-16-281-501
IMEC                     Email: song@imec.be
Kapeldreef 75                   lihuan.song@imec.be
B-3001, Leuven                  lhsong@rocketmail.com
Belgium
======================================================
**************
This e-mail and/or its attachments may contain confidential
information.  It is intended solely for the intended addressee(s).
Any use of the information contained herein by other persons is
prohibited.  IMEC vzw does not accept any liability for the contents of
this e-mail and/or its attachments.
**************