 |  |  | 5.9 Sand to Circuit (Video) |
5.9 Sand to Circuit (Video)
TI (Texas Instruments) produced this video to show what is involved
in manufacturing semiconductors. I expect that this was done mostly
for there own employees. With cleanliness requirments of clean rooms
tours are out of the question. This video is avaliable in the
West Campus Library.
One of the obvious "points" of the video is the real and aparent complexity
of making ICs. Several other aspects of the electronics industry
are less obvious.
First, manufacturing of most electronics today is a photographic process.
The had assembly that was required for vaccume tubes and there associated
connections is all but gone. Today the individual devices are "fabracated"
on the IC by a many step process, but for the most part, hundreds or
thousands at a time. Some steps of the fabrication will batch
process hundreds of wafers at a time. A single 8 inch wafers will have
between hundreds and thousands of inddividual dies. The manufacturing
of Printed Circuit boards is also photograpic. So, for the most part,
the interconnection of individual integrated ICs in a final product
is also photograpic, NOT hand assembly. This helps keeps the costs down.
Second, there are limits to integrated circuits.
- Power limits. If the device gets too hot it burns up.
One of the major limits in IC manufacturing has been caused
by the power used by individual parts of the circuit. To
go faster, it usually has taken more power.
- Circuit Density. Imaging and positioning technology both
limit how small individual features can be on an integrated
circuit. Currently just the lenses can cost over $1,000,000.
As the wafer goes through the process of being made into
integrated circuits it must be positioned over and over
again to be exposed to the new image layer. If it is "off"
the device will not work.
- Wrong kind of parts. Some devices do not integrate well.
Inductors, large capacitors, and crystals are all examples.
Different kinds of circuits have been devised to limit
the need for this kind of circuit. But some are still
required.
I also passed around in class some electronic assemblies. Two of
these included ICs with glass tops. This allows you to see the actual
chip.
One of the other assemblies included surface mount assembly. This is
where the part is held to the board by the soldier. Not by its physical
placement through holes in the board, then being soldered to the PC board.
Instructor: ltaber@pima.edu ** My new Home at GeoApps in Tucson ** The Pima College Site ** The Mad Dr. G.'s home page on phred.
| | | 5.9 Sand to Circuit (Video) |