Silicon Pieces in LamPoly Etcher

Rohan D. Kekatpure rohank at stanford.edu
Tue Nov 9 17:35:25 PST 2004


Greetings Specmat members,

I am a third year PhD student in Electrical Engineering working for Prof. 
Mark Brongersma. My project deals with fabrication of high smoothness 
optical waveguides on Silicon and SOI substrates. As a part of my project, 
I require to etch very narrow (~200nm) trenches. Since I am using standard 
substrates, most people suggested using Lampoly (with an HBr/O2 chemistry) 
in response to my question posted last week on the SNF mailing list.

The purpose of the present mail to request the committee members to 
consider the possibility of allowing the usage of wafer pieces in the 
LamPoly Etcher. Usage of pieces in the Lam would greatly help me in the 
following ways:

1) Because of my dimensions (200nm), the etching procedure is going to 
require tuning and hence many E-Beam-Etching iterations. The only Ebeam 
system that we have currently available is the Raith. It is therefore very 
heavily booked. Moreover, setting it up for writing takes most of the 
reservation time. Hence it would be very time efficient for me if I could 
write several chips on a wafer and then used the cleaved pieces for tuning 
my etching.

2) Above procedure would also increase the amount of output that I can get 
from one wafer and hence would reduce the wastage of substrates.

3) My samples dont have or had any metal on them. They have undergone an 
Ebeam step and I would clean them if it is required to be compatible with 
the cleanliness standard of the machine. The mask that I am planning to use 
is ~500nm thick oxide (no metal mask).

I hope the committee members consider my request favorably as it would be 
of great help in increasing the efficiency of the process as well as 
reducing wastage and freeing up time on a heavily booked equipment.

Thanks you very much.
-Rohan




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