IE 370-Fall 2023
Homework 5
covering
Chapter 19 (Rapid Prototyping)
in the required textbook (Degarmo’s); and
Chapters 8
(Rapid Prototyping)
and
9 (Microfabrica@on)
in the lecture slides.
(Due 11:59 PM EST, December 7, Thursday)
Q1.
The extruder head in a fused-deposiPon modeling setup has a diameter of 1.05 mm and
produces layers that are 0.1 mm thick. If the extruder head and polymer extrudate velociPes
are both 20 mm/s, esPmate the
produc@on @me
for the generaPon of a 20-mm solid cube.
Assume that there is a 3-second delay aSer deposiPon of each layer as the extruder head is
moved over a wire brush for cleaning. (4 points)
Q2.
A chlorine-based polysilicon etching process displays a polysilicon-to-resist selecPvity of 8:1
and a polysilicon-to-oxide selecPvity of 100:1.
a.
How much resist and exposed oxide will be consumed in etching 1500 Å of polysilicon?
(2 points)
b.
What would the polysilicon-to-oxide selecPvity have to be in order to remove only 20Å of
exposed oxide? (2 points)
d
=
1
.
05
mm
n
=
2
=
200
layers
t
=
0
1
mm
V
=
20mm/s
t
=
=
19
.
048s
for
1
layer
20mm
cube
to
3 s
delay
total
=
+
+
+d
=
19
.
048
+
3
A
=
20x20
=
400 mm2
=
22
0485
As
=
dxV
=
1
.
05
.
20
=
21mmY
T
=
Ux
total
=
4409
.
525
Ihr
22
min
selectivity
so
20
1
of
oxide
is
removed
resist
consumption
:
1500(t)
=
187
.
5
i
b)
1500
Oxide
consumption
:
1500l)
=
15
A
=
75
:
/
