TRYEngineering 2024 - 8

STEP 3
Photoresist Coating
After preparing the wafer,
its surface is coated
with a photoresist,
a light-sensitive material.
MAKE: Add another layer
of Play-Doh to model the
photo resistant coating.
STEP 4
Photo Mask
The circuit design is turned into a mask (or stencil).
To make the mask, the circuit design is drawn (or stamped) on the
mask material and then cut out, leaving the mask or stencil of the
" negative of the circuit. " Light then transfers the imprinted circuit onto
the wafer, revealing the parts intended for removal in the next step.
We call this step of making the mask 'tapeout' since the masks used
to be made with tape.
DESIGN MISSION:
Art Infusion
Take on the role of an
Integrated Circuit (IC)
Designer. In order to prepare
you for the design mission
you need to complete the
Integrated Circuit Designer
Certification by creating a
circuit with Play-Doh, fondly
known as Squishy Circuits.
Once you are certified, you will
create the " Mask, " which is a
stencil of the circuit design.
MAKE: Take the index card (cut out a 4 " diameter circle as your wafer)
and map out where to place 6-8 " chips " on your wafer. For this mission,
chips will contain a single LED. There is a twist. In honor of the " Chip
Art " we just learned about, we will turn our chip layout into art.
Two constraints: (1) must have a minimum of 6 " chips "
(2) must have a recognizable image (see image is the " sun " ).
Consider these other samples (mountain and city skyline).
STEP 5
Etching
Etching is the process of removing
unwanted material to create the chip's
features using chemicals that eat away at
the wafer's exposed areas, leaving behind
the desired pattern. It also removes the
underlying layers of silicon and other
materials from the pattern of the
circuit design.
MAKE: Use tweezers to remove the
material exposed from your mask.
tryengineering.org/semiconductors // semiconductors.ieee.org/
https://tryengineering.org/?page_id=29657&preview=true https://semiconductors.ieee.org/
TRYEngineering 2024

Table of Contents for the Digital Edition of TRYEngineering 2024
