Post on 18-Dec-2015
Dilbert
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
High Temperature Furnace(used to grow SiO2 on the wafer)
Robot loader
Gas Control Cabinet
Quartz tube
Quartz wafer carrier
Temperatures can range from 900oC to 1200oC with uniformity of 2oC over a distance of 36 inches
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
Oxygen tanks in service bay
Check oxygen tanks in service bay for proper pressure
Hydrogen tank in service bay
Check hydrogen tank for proper pressure
Furnace gas cabinet-controls the atmosphere inside each furnace tube
Furnace gas cabinet
Gas panel for furnace #6
Verify all gauges read about 20 psi
Nitrogen gas is ALWAYS
“ON”
T/C POS and Auto Ign “ON”
Power lamp does not work
Manual mode only
Loading wafers
Wafers are loaded into
quartz oxidation boats at the furnace.
Quartz boats are NEVER moved or touched
Robot Loader to insert and remove wafers from the furnace
Speed is NOT
adjustedLoad/Unload switch
Wafers entering the furnace
Typical Oxidation Process
1. Load in N2
2. 5 minutes in N2 and O2 (dry oxidation)
3. 30-60 minutes N2+O2+H2 (wet oxidation or steam oxidation)
4. 5 minutes in N2 +O2
5. Unload in N2
Wafers being unloaded
Wafers are unloaded at the
robot arm. Again, the quartz boats are never
moved or touched
Once the SiO2 is formed, the wafers will have a different color, wafer color is based
on the thickness of the SiO2
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
Conductor AttributesCONDUCTOR RESISTIVITY Adherence Cost ADVANTAGES DISADVANTAGES
in ohm cm to SiO2 99.99%
Aluminum 2.65x10-6 Excellent $.06/gm Good Conductor Will corrode/oxidize Easy to coat
Very Inexpensive
Copper 1.67x10-6 Fair $.74/gm Excellent conductor Will oxidize Easy to coat
Inexpensive
Gold 2.44x10-6 Poor $17.00/gm Good Conductor Requires chrome sub layer Noble metal - will not corrode Most Expensive
Easy to coat
Nickel 6.84x10-6 Good $1.20/gm Inexpensive Fair Conductor Chrome 129x10-6 Excellent $.89/gm Poor conductor Fair Conductor Inexpensive Silver 1.63x10-6 Poor $3.67/gm Excellent conductor Requires chrome sub layer
Easy to coat Will oxidizeExpensive
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
Homework• Create a conductor decision matrix using the conductor
attributes chart.• Homework #7 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