Microsoft Word - Homework 3 -Fall 2022.docx
2022 MAE 183B/EE 153/BE 153/ChE 153
Introduction to Microscale and Nanoscale Manufacturing
Homework 3
Due date: Nov 4, 2022 (Friday) 11:59pm
1. For a photoresist, the relationship between exposure energy and thickness after
development is often drawn on a semi-log plot. Therefore, it is important to learn
how to accurately read the value from a log scale plot. What are the values of
point A and point B on the log scale below
2. Thermal expansion mismatch between a wafer and a mask is a potential source of
misalignment in the photolithography process. In your photolithography
experiment, you found that point C (center of the wafer and the mask) between
the wafer and mask is perfectly aligned, but point A is misaligned by 1um. Please
answer the following questions.
(A) How much misalignment will be measured at point B?
(B) If you change the size of wafer and mask to 4”, and the center point C is also
perfectly aligned, how much misalignment you should expect to have in point A?
3. The following schematic shows the standing wave effect during the
photolithography process. The UV light source has a wavelength of 360nm. If the
efractive index (n) of the photoresist (PR) is 1.5. What is the thickness of the
photoresist?
4. Design rules and process flow
(A)The foundry gives below design rules to guide your fa
ication process. Please
describe a process flow that can result in following square a
ay without violating
any of the design rules. Describe the step-by-step processes including the
photolithography, etching, and deposition. You can assume you can use a CVD
method to deposit both the polysilicon and oxide layers, and the CVD deposition
provide uniform coating everywhere even at the sidewalls of the structure. The
etching process is also uniform.
Layer Min
feature
size (μm)
Gap and
spacing
(μm)
Cut in
(μm)
Cut out
(μm)
Enclosure
(μm)
Polysilicon XXXXXXXXXX
Oxide XXXXXXXXXX