My Courses:
Techonolgy of microelectronic devices
Substrate preparation
Film deposition
Modifying the film properties
Lithography
Etching
Tutorials
(
2
)
Wet etching
Dry etching
Fabricating devices
Dry etching
tutorial
Modules
1. Plasma assisted etching
2.
Solid phase etching
pages:
previous
|
1
2
3
4
[
5
]
6
7
|
next
End point detection
It is important to know
how much we should etch
, considering that it is difficult to insure etch selectivity in relation with all other materials
end point detection
- gives and indication of the etching time, by measuring the transparent film thickness with
relectometry
a
laser beam
is send in-situ towards the film (during the etching process inside the reactor) and the
total reflectance
is measured
Total reflectance
: E
r
= E
i
* h(d, n)
E
i
= incident beam
d = film thicknesses
n = refractive index of the film
because the reflactance depends on the film thickness, the
film thickness can be calculated
from the measured reflectance
Etch Rate and Flow
Etching rate increases with increasing the the
flow rate
, because also the concentration of reactants increases
At
high flow rates
, however the reactants are pumped out before before etching can occur, thus the etching rate starts to
decrease
,
as it can be seen on the lower graph in wich etching rate is drawn as a function of flow rate
a maximum in etch rate can be observed, and the suitable etching conditions can be chosen if a high etch rate is desired
1. Plasma assisted etching
2.
Solid phase etching
pages:
previous
|
1
2
3
4
[
5
]
6
7
|
next
go to top
previous | 1 2 3 4 [5] 6 7 | next
Substrate preparation
