FreeLists / si-list / [SI-LIST] Re: Input Impedance Changing

["Yang Rui" <yangrui@xxxxxxxxxxxxxxxxx>]

Hi, Giancarlo,

Thank you for prompt suggestions! We had access to full-wave simulators,
the problem is the impedance between those IC pads was measured without
any global ground, therefore I don't even know the exact impedance with
existence of Al layer as GND.

Regards,
Yang

-----Original Message-----
From: gianguida@xxxxxxxx [mailto:gianguida@xxxxxxxx]=20
Sent: Friday, April 07, 2006 14:21
To: Yang Rui; SI-List
Subject: R: [SI-LIST] Input Impedance Changing


Hi Yang,=20
this seems a perfect topic to rfeply
after the post on Theory vs practice
about model and its validity...:-))))))

I would say that you have two main possibility
make a rough ( that does not mean bad) evaluation of
your problem based on experfience or=20
invest part of your work to use a simulator=20
and create a valid model.

The benifits of your investment are:
1) a better understanding of effects to put some new layer....
2) reuse of the model for next design
3) a tool to explore your problem

At the endo of the day
i would say that you need a simulator...:-))))


Giancarlo


-----Messaggio originale-----
Da: si-list-bounce@xxxxxxxxxxxxx per conto di Yang Rui
Inviato: ven 07/04/2006 6.54
A: SI-List
Oggetto: [SI-LIST] Input Impedance Changing
=20
Hi, ALL,
=20
We had one RFIC with two pads (top layer), the IC works at 2.45 GHz, the
input impedance was 27+180i. The IC was passivated with Si3NI4 layer
with thickness 0.3um. The input impedance measurement was done with GS
probe (The IC does not have global GND). Now we are doing
post-processing of this IC, one more SiO2 layer (thickness 0.3um) was
created on top of Si3Ni4 layer, and one more Al redistribution layer was
deposited on SiO2 layer, the connection to those two pads are brought up
through two vias. My question is that how much will the input impedance
change after inserting this metal layer, what will happen if I short one
via to the Al layer which will be treated as the GND?
=20
Thank you and Regards,
Yang
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This email is confidential and may be privileged.  If you are not the inten=
ded recipient, please delete it and notify us immediately. Please do not co=
py or use it for any purpose, or disclose its contents to any other person.=
 Thank you.
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