Dilbert

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Dilbert
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Next steps in the antenna fabrication process

• Create a dielectric surface. The antenna must
  sit on a dielectric or insulating surface, not a
  semi-conducting surface.
• Determine the best conductor for the antenna.
  The actual antenna will be made out of a
  conducting metal

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High Temperature Furnace(used to grow SiO2 on
the wafer)
Gas Control Cabinet
Robot loader
Quartz tube
Quartz wafer carrier
Temperatures can range from 900oC to 1200oC with
uniformity of 2oC over a distance of 36 inches
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Furnaces are color coded to prevent
contamination. Furnace 7 is marked as RED
and is used only for silicon dioxide formation on
virgin clean wafers
Quartz wafer carrier is never removed from robot
arm
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Oxygen tanks in service bay
Check oxygen tanks in service bay for proper
pressure
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Hydrogen tank in service bay
Check hydrogen tank for proper pressure
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Furnace gas cabinet-controls the atmosphere
inside each furnace tube
Furnace gas cabinet
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Gas panel for furnace 6
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Verify all gauges read about 20 psi
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Power lamp does not work
Manual mode only
Nitrogen gas is ALWAYS ON
T/C POS and Auto Ign ON
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Loading wafers
Wafers are loaded into quartz oxidation boats at
the furnace. Quartz boats are NEVER moved or
touched
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Robot Loader to insert and remove wafers from the
furnace
Speed is NOT adjusted
Load/Unload switch
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Wafers entering the furnace
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Typical Oxidation Process

1. Load in N2
2. 5 minutes in N2 and O2 (dry oxidation)
3. 30-60 minutes N2O2H2 (wet oxidation or steam
   oxidation)
4. 5 minutes in N2 O2
5. Unload in N2

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Wafers being unloaded
Wafers are unloaded at the robot arm. Again, the
quartz boats are never moved or touched
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Once the SiO2 is formed, the wafers will have a
different color, wafer color is based on the
thickness of the SiO2
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Besides being a dielectric (insulating) layer,
the SiO2 has another very important role to play
in microelectronics, that of a barrier to the
doping of silicon
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n-type silicon wafer shown in cross-section
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At high temperature with an oxygen atmosphere the
silicon dioxide forms on all silicon surfaces
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Using a photolithography process, small holes are
created in the silicon dioxide exposing bare
silicon
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Again, at high temperature, a p-type dopant
(boron) is introduced. The boron can not
penetrate the silicon dioxide but can penetrate
the bare silicon and diffuses into the silicon
forming a p-n junction
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If a diode was the end product, the silicon
dioxide is removed from the back side (if not
already removed in previous steps) and metal
contacts, usually aluminum are deposited on top
and bottom creating a p-n diode. For more
complex devices, the steps are repeated
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Once the dielectric has been formed on the
silicon wafer

• It is time to decide on a conductor to create the
  antenna.
• Conductor attributes will be evaluated
• Your team will create a decision matrix using a
  simple EXCEL spreadsheet to determine the
  conductor for your project
• The conductor chosen will be deposited on your
  wafers next week

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Conductor Attributes
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Sample Conductor Decision Matrix

• Create a title for the spreadsheet
• Decide on weights for each attribute
• Decide on conductor rank for each attribute
  based on attributes chart
• Multiply weight times rank for each conductor
• Add the columns
• The conductor of choice is the one with the
  largest total

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Homework

• Create a conductor decision matrix using the
  conductor attributes chart.
• Homework 9 on the web site
• Both the conductor attributes chart and a sample
  decision matrix are available on the web site
• This is a team assignment, only one per team
• Preview before submission
• Make sure entire spreadsheet prints on one page
• Include Title with team name
• Use gridlines
• Highlight the conductor of choice