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Final

VIEWS: 24 PAGES: 23

									              IBM GROUP 8
                        Spin Coater




                       Final Report

Group Members: Gregory Burtt, Gregory Hewitt, David Valente

               Factory Mentor: Jeff Marshall

               IBM Contact: Kevin Remillard
                                                          Contents
Project Summary........................................................................................................................................... 2
   The Problem .............................................................................................................................................. 3
   Statement of Need .................................................................................................................................... 4
   Proposal .................................................................................................................................................... 4
   Team Charter ............................................................................................................................................ 4
Evolution of the Design ................................................................................................................................. 4
       1st Semester ......................................................................................................................................... 4
       2nd Semester ........................................................................................................................................ 5
The Final Design ............................................................................................................................................ 6
Testing ......................................................................................................................................................... 11
Accounting Expenditures ............................................................................................................................ 19
Return on Investment ................................................................................................................................. 21
Success ........................................................................................................................................................ 21
Appendices.................................................................................................................................................. 22




                                                                                                                                                                       1
                       Project Summary
        IBM is having defects in their photoresist spincoating machines associated with a
buildup of dried resist on the bowl that is meant to catch the spun off fluid. There is a regular
cleaning cycle meant to clean any resist buildup with a spray of solvent. Our goal was to
redesign a part in this cleaning process in order to better facilitate fluid flow to the location that
was being missed by the current cleaning process. A test stand was built at UVM to mimic the
components and performance of the machines in use at IBM. Many different modified
configurations of the cleaning part were tested, until a final design was chosen that best
retained IBM’s cleaning configuration while getting solvent to a previously untouched part of
the bowl. Testing of both the modified cleaning parts and the original cleaning set up were
done with the test stand, as well as at IBM. Long term testing of both the modified cleaning
apparatus and the bowl has not yet been completed at the time of this report, so final
conclusions for the long term cost effectiveness for IBM cannot be specified. In parallel, contact
with a company advertising coatings provided us with a sample on a bowl set. This will be going
through long-term tests at IBM that were not able to fit into the timeframe for this project.




                 Figure 1: Schematic - Wafer Process and Formation of Build Up


                                                                                                         2
The Problem
         IBM uses a spin coater during their photolithography process to apply photoresist to a
thin silicon wafer. During this process, the fluid is injected onto the surface of this wafer while it
is spinning at speeds up to 7500 RPM. The spinning motion precisely coats the wafer and sheds
excess fluid off the edge; a surrounding bowl collects and directs the fluid downwards with the
help of a powerful vacuum. Every twelve hours, the machine uses a cleaning process to similarly
send solvent through a disk specifically designed to reach any point on the bowl that this
photoresist chemical may have dried. Unfortunately, the cleaning disk poorly cleans an area
above a horizontal plane. As a result after two weeks of photoresist drying at this location,
defects can occur on the silicon wafers, thought to be caused by to a change in airflow as a
result of the buildup on the bowl.




                 Figure 2: Schematic - IBM’s current cleaning disk configuration




                                                                                                         3
Statement of Need
        Like clockwork, IBM will get defects appearing on wafers every two weeks. In order to
curb this problem, photolithography machines are shut down and the bowls are manually
changed. The removed bowls are outsourced to a cleaning company, then later returned and
reinstalled. Our goal is to reduce the buildup on these bowls so IBM can run the bowl longer
without defects, thereby decreasing machine downtime resulting in an increase of production
capacity, and decreasing cost from less frequent bowl cleanings.

Proposal
       The project had been narrowed to three possible avenues. We could explore the
cleaning disk, a possible bowl coating, or the airflow through the bowl set. It was decided that
the cheapest and most effective solution would be to focus on the cleaning disk, with a
secondary focus on a possible bowl coating due to a lead provided by IBM.

Team Charter
         By April 30th, 2008 a final cleaning disk prototype, cleaning recipe, and bowl coating decision
will be made that will reduce the frequency with which the bowls are removed for cleaning. Initial
testing will be performed to observe cleaning solvent behavior and collect empirical data on the
performance of the current cleaning disk, and compare performance of the current bowl with a bowl
coated with Nx-Edge tt-Kote. After initial testing, the disk design will be refined and a prototype will be
manufactured and tested in both the coated and uncoated bowl sets. Modifications and testing will
continue to be performed on the prototype disk until a satisfactory final design is engineered. The
results of the testing, the final cleaning disk design, cleaning recipe, and bowl coating decision will be
submitted to IBM.




              Evolution of the Design
1st Semester

        September 12th 2007: Decision to focus upon the cleaning disk as a design project.

        September 19th 2007: Discussion of possible cleaning disk design elements. Ideas include
nozzle passages, rotary squeegee attachments, smoother fluid collection paths, and simple
things like angled holes and slots.




                                                                                                              4
       September 26th 2007: Hand drawings of rotary squeegees appear out of the wild.
Solidworks drawings start to take a real form. Difficulty of manufacture of things like nozzle
passages begins to be realized.

        October 9th 2007: Two cleaning disk models have been created in Solidworks. Rotary
squeegees were thrown out due to size constraints. The two models were ranked using a Pugh
chart, a single design remains.

        November 15th 2007: The disk comes back into focus after a month of thinking about
test stand design. Ease of manufacture is becoming a very important factor; new ideas are
brainstormed for next semesters testing.

      December 6th 2007: It’s been decided by this point that we would not create a new disk,
but modify IBM’s existing disk with several different hole patterns. Many different ideas were
drawn up to be tested for the following semester.

2nd Semester

       February 27th 2008: The test stand is complete allowing for complete evaluation of
IBM’s current disk.

       March 5th 2008: Test stand problems of balance at high RPM prevent much from
developing.

        March 19th 2008: Test stand problems solved, the original disk is completely classified.
The first testing modification made, holes in the top of the disk is tested and fails.

        March 26th 2008: All initial designs do not get the fluid where we want. Breakthrough
test of disk without its spray skirt jumpstarts final design idea.

        April 2nd 2008: Roughly made top disk with wide grooves for fluid to flow up and out of
the disk at a higher angle does the trick. Testing at IBM to follow the very next day.

       April 22nd 2008: Final clean prototype made and ready for final testing at IBM.




                                                                                                   5
                       The Final Design
In order to fully understand how our final working prototype works, it’s best to understand the
environment that it inhabits. The following is the test stand we created:




                                  Figure 3: Photo – Test Stand

The cleaning disk distributes the fluid onto the bowl set, which captures all shed fluid and
brings it to a drain. The wooden structure behind our test stand provides the gravity potential
required for proper backside rinse nozzle flow speed. The gas can is where our drained fluid
ends up, and that tubing going out the back left originates at a leaf blower, which provides the
vacuum. The speed of which was adjusted with a valve and calibrated using a vane
anemometer borrowed from IBM.




                                                                                                   6
To get a feel for how this operates, the below picture gives you a peek inside:




                                    Figure 4: Photo – Cleaning Disk Parts

       The cleaning disk itself is 3 discrete pieces held together by mounting screws through
the top of the disk. The chuck mount is a flat circular piece of plastic designed to be held by
IBM’s vacuum chuck. It’s held on by four screws and centered by a locating pin that runs
through the top of the disk. The skirt contains fourteen .95mm holes pointing in varying angles;
from straight out to approximately 45 degrees downward. There were also eight larger holes
pointing straight down to clean a second piece of the bowl set. The build up of photoresist was
above the highest holes and the disk and it had no way to bring solvent to these higher areas.

         You can also see how the disk distributes fluid along the side of the bowls. The two
backside rinse nozzles direct jets of fluid into the cavity created by the skirt and the top of the
disk. As the disk spins, the fluid follows the top of the disk into the skirt, at which point the fluid
is distributed to the holes and sprayed outwards or downwards, depending on the hole.




                                                                                                          7
                        Figure 5: Photo - Cleaning Disk Jet Visualization

The original cleaning disk IBM is currently using is seen above. Though the holes are too small
to see, the jet of fluid escaping is visible.

       The final prototype modified the top portion of the disk to contain two wide channels
that angle upwards and exit just shy of where the top meets the skirt to screw in. The fluid
follows these two channels and exits upwards to contact the buildup area. Though this will
bypass two fluid exit holes on the side disk, the suction as well as gravity pulls solvent back
down across the areas that would normally be contacted through these jets from the side skirt.
There are also twelve holes in the side skirt that are not bypassed. This solution was designed
for minimum modification cost. Both the complex skirt and the chuck mount remain
unmodified.




                                                                                                  8
 Figure 6: Schematic – Final Prototype




Figure 7: CAD Drawing – Final Prototype




                                          9
        The challenge was to discover what the fluid was doing inside the disk. Our initial
calculations, verified by tests, showed that almost fluid would build up inside the ring of the
disk at the 2500 RPM cleaning cycle, so any holes set back from the skirt walls would not have
any fluid flow through them. Furthermore, it was found the fluid was flowing along the top of
the disk instead of flowing freely around inside the cavity. The velocity of the fluid relative to
the spinning disk prevented any from escaping through holes drilled in the top of the disk. The
fluid would simply flow over the openings instead of through. A comprehensive discussion of
the testing and results follows.




                                    Figure 9: Photo – Final Prototype




                                                                                                     10
                                         Testing
After constructing the test stand, it was decided to follow the following test schedule.

1) Analyze original disk
   a) Determine contact height
      i) Using strips of paper to determine point of contact
      ii) Using printer ink swabbed on inside of bowl
   b) Determine direction of fluid flow and corresponding amounts
      i) Does flow come out side holes of bottom holes? How much from each? Perform qualitative
          analysis of fluid velocity
   c) Observe properties of the exiting fluid
      i) Does the fluid exit as a jet, spray, or vapor?
   d) Characterize the coverage of the fluid upon the bowl surface
      i) Does the fluid cover the bowl in a uniform manner or is the coverage patchy with rivulets?
2) Analyze Prototype:
   a) Repeat steps a-e.
3) Draw conclusions. Modify prototype as necessary.


First we analyzed the original disk given to us by IBM. We quickly determined the contact height using a
strip of paper taped to the inside of the bowl. The height at which the fluid contacted the bowl was
easily determined as a distinct line of wetness would appear on the paper. As an initial value, the
average contact height was found to be 22.86mm. (Contact height refers to the distance from the top of
the outer bowl to the point where the fluid makes contact with the side of the bowl. A lower value for
contact height means that the fluid strikes the bowl higher, which in this case is desirable.) We soon
found that the “Paper Test” was not accurate because the water would quickly wick up the paper,
making it a time-dependent test. But the test provided an initial metric. Next we performed test (b). The
data is shown below in Test #1.




                                                                                                            11
Test #1

Fluid Flow Analysis of Original (POR) Disc                             The test revealed that the original
                                                                       disk cleans the bowl very effectively
                                                                       at 50 and 100 rpm. At 50 rpm, all
            (% of Mass Flow)                                           the fluid coming from the nozzles
                                                                       beneath the disk exits through the
            Bottom          Side
RPM         Holes           Holes        Observations                  eight larger holes in the bottom ring.
                                                                       These holes provide a path for large
                                         Bead forms on top of lip of   droplets to fall onto the inner bowl.
       50            100              0 inner
                                                                       These droplets evenly coat the lip of
                                         bowl, celeaning lip properly. the inner bowl, cleaning it
                                                                       thoroughly. At 100 rpm, all the fluid
                                         Large droplets spin out and
                                                                       continues to exit from the bottom
     100             100              0 land
                                                                       holes, but with enough centripetal
                                         on surface of inner bowl.     acceleration to fly out and land on
                                                                       the surface of the inner bowl. This
                                         Large droplets contact outer
                                                                       action appeared to be designed to
     200             100              0 bowl
                                                                       clean the surface of the inner bowl.
     300              70            30                                 At around 300 rpm, the fluid begins
                                                                       flowing out the side holes of the
     500              50            50 Medium size droplets
                                                                       disk. By 600 rpm, all the fluid exits
     600                0         100 Can see trajectory of individual from the side holes. The fluid exits
                                                                       as a stream that collects into
                                         particles streaming from side
                                                                       relatively large particles of fluid. At
    1000                0         100 hole
                                                                       600 rpm these particles actually
                                         in 600-1000 rpm range         have the ability to travel furthest
                                                                       from the bowl. By removing the
                                         Mixture of atomized particles
    2500                0         100 and                              outer bowl, we measured the radius
                                                                       and observed the trajectory of the
                                                droplets
                                         smallrpm, the radius was greatest and decreased with increasing
fluid particles exiting the disk. At 600-800
                                   size, Atomized vapor cloud with no
rpm, due to decreased particle 100 the momentum to air resistance ratio decreased. At 2500 rpm, the
    5000                0
flow is a stream of fluid coming from the side holes and generally turning to a vapor of atomized
particles. At 5000 rpm, the fluid exits droplets.
                                          quickly enough as to become entirely populated by atomized
particles, creating a cloud of vapor that hovers around the disk.

         Next Prototype 1 was tested. Initially, the functionality of the disk was tested. It was found that
no fluid would exit the hole drilled into the upper disk at a 35 degree angle. It was concluded that the
centripetal acceleration acting on the fluid would not allow it to make an abrupt change in direction so
as to follow the upward passage. From this and the previous test, a picture of the motion of the fluid
within the disk became clearer. It was originally thought that fluid pooled within the bottom ring of the
disk as centripetal acceleration forced the fluid into the cavity. However, this cannot be the case or else




                                                                                                                 12
fluid would escape both from the prototype hole in the top disk and the bottom holes. The fluid flows
more as a river. Instead of gravity guiding the river in its place, centripetal acceleration and contact
forces direct and guide the thin film of fluid.

 Test #2

 Prototype 1 Testing

 (One 1/16" hole drilled in top disk at 35 deg from horizontal)



             Results (Exit/Not
 RPM         Exit=yes/no)

      100    No

    1000     No

    2500     No

    5000     No



 Conclusions: Possible causes for no fluid flow through hole:

 Fluid does not flow into passages with axes non-parallel

 to flow acceleration.

        It was decided then to drill holes in bottom ring where it was thought fluid could readily enter
the passages. A problem was encountered, however, given the geometry of the disk and the bowl. In
order to contact the bowl at the desired height, the holes would have to be drilled at a 50 degree angle
upward with the entrance to the hole lying at the bottom of the ring (where we found that no fluid was
flowing.) Therefore, Prototype 2 was not a success.

Test # 3

Prototype 2 Testing

(4 holes drilled in bottom ring at 50 deg from horizontal)



RPM         Results

   1000     No significant increase in contact height over original disc

   2500     No significant increase in contact height over original disc




                                                                                                           13
Test # 4

Prototype 3 testing

(Upper disc bent into parabolic shape. No bottom ring. Same outer

dimensions as original disc.)

(Contact height measured using paper test)



Knee Height: 19.20 mm



             Contact height
RPM          (mm)                Results

   2500                   23.5   No droplets on upper ring of outer bowl.

                                 Fair amount of large droplets forming on

                                 the knee.

   1000                   22.3   Large amount of liquid on knee

    600                   22.6   Not as much liquid on knee as @ 1000

75-80        NA                  Cleans inner bowl surface effectively

        60   NA                  ~25% of droplets fall on top of lip of inner

                                 bowl providing moderate cleaning

                                 effectiveness.




         From the previous tests, it was determined that one solution would be to utilize the contact
forces of the fluid with the top disk. By gradually turning the fluid upward along the surface of the top
disk, the fluid could be directed at the correct angle by the time it reached the end of the disk. By
removing the bottom ring of the cleaning disk so that only the top disk remained, the top disk was bent
by hand into a parabolic shape with overall dimensions still the same as the original. The results are
recorded in Test # 4. Prototype 3 contacted the bowl at a greater height than the original, showing that
the concept of utilizing the contact forces held great opportunity. At approximately 22.5 mm, the



                                                                                                            14
contact height was still not sufficient, seeing that the knee is located at 19.2 mm, the goal being a
contact height of about 18 mm.

                                                                     Prototype 4 was then constructed by
Test # 5
                                                            removing two slots from the original disk
Test Prototypes 4,5,6,7                                     design. The slots were shaped so that the fluid
                                                            was gently turned along a parabola. By exiting
(4) : Two slots cut out of top disc tested at IBM 4/15/08
                                                            from the top of the disk, the contact height of
(5) : Modification of (4) to raise contact                  the fluid is already raised an added three to
height                                                      four mm from the original. Given the upward
                                                            angle with which it exits, the contact height
(6) : Modification of (5) in similar manner
                                                            raised a bit more. The data are shown in Test
(7) : Set slots back 1/10" to raise contact height          #5.



Contact height measured using ink test: Swab printer
                                                            Prototype 4 was a success having attained the
ink
                                                            18 mm mark. This prototype was brought to
on three locations around the inner surface of outer        IBM and tested on the 15th of April, 2008.
bowl.                                                       Prototypes 5, 6, and 7 are replicas of
                                                            Prototype 4.

Knee Height: 19.20 mm                                                Here are notes from the 4/15 IBM
                                                            visit.

                                                            Solvent vs. Water- Observations of the
All tests at 2500 RPM
                                                            differences noted between the two fluids in
                                                            the cleaning process

             Contact Height                                 -Solvent forms sheets on the bowl, not large
Disc         (mm)                                           droplets.
Original                    21.77                           -This occurs at all tested rpms
Prototype
                                                            -At 100 rpm, solvent acts similar to water in
4                           17.91
                                                            the way it exits the cleaning disk: large
Prototype                                                   droplets from bottom holes.
5                           20.27
                                                            -Similar behavior between water and solvent
Prototype                                                   in the way they flow through and out of the
6                           19.13
                                                            disk.
Prototype
                                                            -Solvent evaporates much faster from bowl
7                           18.31
                                                            surfaces than water.




                                                                                                              15
Test # 6
                                                                Cleaning Effectiveness of Original Disk

Final Testing at IBM of Prototype 6 on 4/24/08                  -Relief behind knee has resist built up in
                                                                a 3-4mm strip that is not cleaned off.

                                                                -Leaves bowl surfaces very wet with
Fluid type : Solvent
                                                                solvent after cleaning.
Knee
height:                 19.2   mm                               -Fluid does not contact the majority of
                                                                the knee, if not any.

                                                                -Small amount of resist left on knee after
Particle Test: Number of particles in air surrounding bowl
                                                                cleaning.
while cleaning process runs.
                                                                Cleaning Effectiveness of Prototype

                                                                -Cleans knee and relief behind knee
XMO: 1.)Run cleaning process                                    thoroughly.
2.) Coat three wafers                                           -Cleans to about 2 mm above the knee
3.) Identify number of particle defects on each wafer.
                                                                -Cleans surfaces of inner bowl similarly
                                                                to original disk

             Particle          Contact Height      XMO          -Greater amount of solvent along and
Disc         Test              (mm)                Defects      above knee of outer bowl. (This might be
                                                                a negative consequence.)
Original                  0                21.34   minimal

Prototype                 0                17.78   minimal      -General spray characteristics seem
                                                                similar to original.



         After testing at IBM, the final prototype (7) was produced as a slight modification of Prototype
4. This prototype was tested in Test # 5 to determine the contact height using the “Ink Test.” This disk
was brought to IBM and tested on 4/24/08. For both the original and the prototype, the contact height
was tested and the results are shown in Test # 6. Prototype 7 met the standards we set for proper bowl
cleaning. Airborne particle tests were then run on both the original and prototype disks by placing a
hose next to the bowl connected to the device which counted the number and size of particles collected
at the hose entrance. The device counted zero particles over the entire cleaning process (three minutes)
for both the original and the prototype. If particles of solvent were found to be exiting the top of the
bowl to great extent, the chances of defects due to solvent landing on wafers soon after the cleaning
process would be high. Next, wafers were processed immediately after the cleaning process using both
the original and prototype disks. Each disk was followed by the processing of three wafers in a row. The



                                                                                                             16
prototype was cycled twice, giving a total of six wafers run behind the cleaning process. These nine
wafers total were inspected for defects using a scanning device that IBM uses to continually monitor
wafer defects. The device takes pictures of the wafer in rows spaced ¾ of a micron apart, and detects
areas of defect and registers their size. All nine wafers passed the inspection. The six trailing the
prototype had no more than three defects each (no greater than a micron in size) over the entire wafer.

`The graph below shows the distance from the top of the outer bowl to the knee in purple, the distance
from the top to the fluid contact point of the original disk in brown, and likewise for the prototype in
green. Our goal was to cause the fluid to contact the bowl at a height about two millimeters above the
knee. As can be seen, the goal was met.


                                 Comparison of Contact Height

                            22

                            21

                            20
           Contact Height




                            19                                            Original
                                                                          Prototype
                            18                                            Knee Height

                            17

                            16

                            15

Here are the notes taken at IBM on 4/24/08

No particles generated by either POR disc or UVM disc
Droplet formation on the top edge of top bowl was negligible
Contact distance: distance from top of outer bowl to given point.
POR: .84 "
UVM: .70 "
knee .756 "

Picture numbers:
up to 1306: resist before cleaning
1307-1309: POR cleaning results



                                                                                                           17
1310-1314: UVM cleaning results

Particle testing:
Particle sizes from .1 to 1 micron were looked for with a particle
detector when the cleaning disk was run. 0.9cfm of air was tested for
three minutes with zero particles detected for both the UVM* and POR
disks. The particle collector was positioned as close to the edge of the
bowl as possible to maximize collection.

*UVM disk showed a low number of particles of various sizes on the first
couple runs, but the next two tests detected zero particles, this was
most likely from debris on the disk

XMO's:
.75micron lines on 6 wafers after UVM disk and then on 3 wafers after POR
No extra defects on the post-UVM XMO wafers compared to the post-POR XMO's.

Notes:
UVM: Small ring of solvent forming where chuck contacts cleaning disk.
This is never found on the POR and is a problem.
Possible causes:
1.) Small scratches found on bottom of disk, causing vacuum to leak
between chuck and disk, sucking solvent out of surrounding air and onto
chuck.
2.) Disk chuck base not centered properly on vacuum chuck, causing corner
of disk chuck base to intersect solvent jet from inner solvent nozzle.
(This nozzle is .5 mm from corner of disk chuck base normally)

*Option (1) found to be the case after further testing.



In conclusion, initial testing showed that Prototype 7 is a suitable design for a new cleaning disk that will
modify the fluid contact point so that resist is removed from a height approximately two millimeters
above the knee while still functioning similarly to the original disk in all other regards. Further long term
testing is needed to prove whether or not the prototype extends the length of time that the bowl can
remain within the Tel machine before defects due to resist ball-bearings increases beyond a tolerable
number. Currently, bowls are cycled in and out of Tel machines every two weeks to be cleaned. Ideally,
the prototype will increase this cycle time to four, six, eight weeks, or more.




                                                                                                                18
                 Accounting Expenditures
        The overall cost of the project was $1,815.71. This includes the cost of constructing the test
stand and of machining prototypes. Wood was used for basic structures instead of aluminum to keep
the cost of the test stand low and make assembly go easier. Using the Toro leaf blower as an exhaust
pump also helped to reduce the cost of the test stand. Below is a list of the materials used and their
costs.

Expenditures:

                                                       Price
 Description                          Supplier         Each    Quantity   Cost per Item   Use

 Stepper Motor                        Animatics      $779.00      1       $      779.00   Motor to spin cleaning disk/wafer

 Power Supply                         Animatics      $329.00      1       $      329.00   Power supply regulator for motor

 Cable set                            Animatics      $186.00      1       $      186.00   To control and monitor motor from laptop

 Toro 12 Amp Blower                   Amazon.com      $69.97      1       $       69.97   Vacuum for exhaust airflow

 Shipping charge                      Amazon.com      $11.95      1       $       11.95

 Acrylic Sheet, 1/4"x2'x2'            Tap Plastics    $25.00      5       $      125.00   Enclosure for bowl set

 Acrylic Cement                       Tap Plastics     $5.95      1       $        5.95   Assembly of acrylic parts

 Acrylic Hinge (2-pack)               Tap Plastics     $1.95      1       $        1.95   Hinges for plexiglass case

 Clear Hasp Set                       Tap Plastics     $1.95      1       $        1.95   Latch to secure the top of test bed

 Shipping Charge                      Tap Plastics    $40.33      1       $       40.33

                                      McMaster-
 1.5” PVC Vacuum Hose                 Carr             $4.77      5       $       23.85   Pipe to connect leaf blower to bowl set

                                      McMaster-
 1.5” Polyprop Pipe to Hose Adapter   Carr             $1.33      4       $        5.32   Connect pipe to threaded fittings

                                      McMaster-
 2.25” Worm Drive Pipe Clamp          Carr             $7.39      1       $        7.39   Clamp pipe to fitting

                                      McMaster-
 1.5” NPT x NPT Tee                   Carr            $10.37      1       $       10.37   Connect two exhaust ports together

                                      McMaster-
 1.5” PVC Globe Valve                 Carr            $20.89      1       $       20.89   Control exhaust parameters

                                      McMaster-
 1.5” Nipple NPTxNPT                  Carr             $2.13      1       $        2.13   Connect Valve to tee

                                      McMaster-
 1.5"x1' Aluminum Rod                 Carr            $11.96      1       $       11.96   Stepper motor Shaft




                                                                                                                                     19
                            McMaster-
Assorted Drill Bits         Carr               $8.00      1    $       8.00   Drill holes in Prototype

                            McMaster-
1/4" in-line filter         Carr               $3.57      1    $       3.57   Filter water before nozzles

                            McMaster-
Shipping Charge             Carr              $24.43      1    $     24.43    Delivery fee

Teflon Tape                 Home Depot         $0.99      1    $       0.99   Seal pipe fittings

Combination Lock            Home Depot         $5.57      1    $       5.57   Lock to protect bowl set from theft

Plywood ¾''x2'x4'           Home Depot        $10.98      1    $     10.98    Structure to secure bowl set

Plywood 1/2''x2'x2'         Home Depot         $4.48      1    $       4.48   Base for water stand

1"x3"x8' Spruce             Home Depot         $1.27      4    $       5.08   Water stand structure

2"x3"x8' Stud               Home Depot         $1.49      4    $       5.96   Water stand structure

3"x2' PVC pipe              Home Depot         $4.51      1    $       4.51   Structure to secure shaft with bushing

Flex CPLG                   Home Depot         $5.98      1    $       5.98   Adapter for exhaust system

Flex CPLG                   Home Depot         $4.48      1    $       4.48   Adapter for exhaust system

Flex CPLG                   Home Depot         $7.98      1    $       7.98   Adapter for exhaust system

Caulk                       Home Depot         $2.97      1    $       2.97   Sealent

15' Electric Cord           Home Depot         $8.97      1    $       8.97   Power exhaust

3/8"x30' vinyl pipe         Home Depot         $8.07      1    $       8.07   Water system

2 gal. gas can              Home Depot         $3.97      1    $       3.97   Capture waste water

13 QT Waste Basket          Home Depot         $5.97      1    $       5.97   Water holding tank

3/8" Valve                  Home Depot         $7.56      1    $       7.56   Water system valve

3/8" Tee                    Home Depot         $4.20      1    $       4.20   Water system

1.5' Vinyl Tube             Home Depot         $3.00      5    $     15.00    Waste water collection

Tax                         Home Depot         $8.24      1    $       8.24

Printer Ink Magenta 16 oz   ink4inkjets.com   $19.99      1    $     19.99    Fluid to simulate resist

Shipping Charge             ink4inkjets.com    $5.75      1    $       5.75   Delivery fee

                                                       Total   $   1,815.71




                                                                                                                       20
               Return on Investment
       Unfortunately, a quote to modify the sixty disks that IBM will need done is still in
progress at Whitetail Manufacturing. IBM currently spends $170,000 a year on trucking and
cleaning costs for the bowl sets, a portion of which will be saved with a reduction in necessary
bowl changes. With a decrease in bowl change frequency of 50%, IBM predicts the following
increases in production capacity.




That is just shy of a 29200 wafer per year increase in the 16 tools that run this cleaning process.




                                     Success
        Our original charter said we would reduce the frequency in which it is necessary to
remove the bowl set for cleaning. In that respect, our prototype, it is believed, will prove to be
a great success. As a result of delivering solvent to the problem area, the bowls should be able
to stay in for at least a projected two weeks longer, double the current time. Indeed, IBM is
going to be testing the disk and coated bowl set for several months before final conclusions are
made. Concerning the coated bowl set, it was not within our capability to test the coated bowls
at UVM or within the timeframe of the project due to the need for long-term testing. Although
we did get the bowl coated (for free as a demo), we did not give IBM a final decision on
whether the coating was worth the cost. As a result we have passed the exhaustive testing of
the prototype and bowl over to IBM, at the conclusion of which, we will know the degree of
success of our prototype.




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                               Appendices
I)   Flow calculations from Mathematica. For preliminary work, see the following page.




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