Question

Type into Google: "globalfoundries sand to silicon", and a Youtube video will come up (accessed on 3/17/2020). The address is:

youtube.com/watch?v=UvluuAIiA50

Watch more than once if needed.

The video will go over various parts of the process steps in making a silicon computer chip integrated circuit (IC). On this page (and on the back if needed):

1. List (in order) the major steps in the fabrication process described in the video set. I do not expect you to have a detailed description of each step – just write down the "highlights".

2. Explain why the ICs are fabricated in the "clean rooms" depicted in the video.

3. A representation of the silicon crystal is used in some of the animations in the video. Explain what is wrong with the representation.

Answer 1

1.

a. Circuit diagram

b. Silicon Wafer making from sand

c. Photo Lithography to draw the outline of the cicuit using UV light

d. etching to remove the undrawn part on the wafer

e. Ion implantation to dope impurities on the wafer and make a transistor

f. Cleaning of the remaining wafers, to remove unwanted impurities deposited on wafer

g. Copper deposited for metal contact, to establish connection between and transistors and also with the chip

h. Grinding to isolate each inter connects, to isolate the copper contacts so that there is no short circuit between the circuits

i. Characterization of individual transistor using electron microscope, to cross check weather the required circuit is fabricated or not

2. As mentioned in the video the electrical properties of Silicon(any semiconductor) can be changed by adding impurirties. Addition of impurities also induces defect sites inside the silicon crystal. Hence one must see that there are no impurities present while fabricating an integrated circuit. In the above context a clean room is used.

3. In the video the structure of Silicon is shown as simple cubic but however the exact structure of single crystal Silicon is tetrahedral (or diamond cubic)