1 NLS-030 LOGITECH PM5 LAPPING & POLISHING MACHINE ...

LOGITECH PM5 LAPPING & POLISHING MACHINE
Primary contact: Chih Chen X54593
PREPARED BY: Chih Chen DATE 6-15-2000
Assoc. Devlp. Engr.
Superusers:
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Extension
Hung Nguyen X57338
Paulo S. Motta X45774
Jeff Yao X45435
NLS-030

1.0 SCOPE
This document establishes the procedures for lapping and polishing of silicon, GaAs, InP
and other substrates in the Nanoelectronics Laboratory.
2.0 APPLICABLE DOCUMENTS
Logitech logbook and maintenance log
System Component Operation Manuals
3.0 MATERIALS AND EQUIPMENT
Logitech PM5 System
Precision Jig
Autofeed cylinder
Glass substrate
Abrasive Al2O3 powders
Chemcloth, 12” in diameter
Polishing Cloth fir planarization
Chemlox CMP solution
Chemical-resist cylinder
Colloidal silica
Wax-Ocon-195
Opticlear-
Isopropyl Alcohol
Gloves, cleanroom
Cleanroom wipes
Cleanroom mask
4.0 GENERAL
4.1 Logitech PM5 The Logitech CMP uses abrasive slurry and chemical
solution to lap and polish silicon, GaAs, InP, and other substrates in
Nanoelectronics Lab.
4.2 Precision Jig The unit measures the thickness of sample during lapping,
and shuts down the machine automatically after lapping the programed
amount of material.
4.3 Machine Maintenance Maintaining a smooth and convex plate surface is
needed to obtain uniform lapped surface. Maintaining a clean environment
is necessary to obtain a uniform surface finish. To avoid scratches on the
plate surface and exclude agglomerated particles, these steps are to be
followed:
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4.3.1 Pay great attention when placing test blocks and the precision jig on
the lapping plates. Never make scratches or chips on the lapping
plates.
4.3.2 Always clean the cylinder, stage, glass substrates and the jig
thoroughly and completely whenever changing one slurry to
another.
4.4 Emergency Power Shut Off
PROCESS PREPARATION
4.4.1 Push in the "Stop" button which is located on the front of the
machine.
5.1 Sample Mounting Before lapping, samples must be mounted on glass substrates.
Samples must be mounted on the flat side of the glass substrate which is indicated
by an arrow marker “∧ “ on the edge of the glass substrate.
5.1.1 Clean the glass substrates with opticlear, then alcohol, and rinse by DI
water. Blow dry or wipe dry with clean room wipes.
5.1.2 Place sample on the substrate facing down. Measure the thickness of the
sample by the dial micrometer on the table next to the machine. See
APPENDIX Ia for the operation procedure of the dial.
5.1.3 Place the glass substrate on the hotplate and turn the temperature to 100
set point (150 for black wax). After ~10 min or when the temperature
reading is 70 to 80°C, proceed to the next step.
5.1.4 Place a very small amount of wax in the center of the glass substrate with
the metal spatula (stored in the tool box). For most applications the white
wax, (ocon-195 in a can at the station), should be used. For very small
samples or when thinning down to < 20um, the black stick wax may be
used.
5.1.5 Spread the wax uniformly on an area slightly larger than the sample to be
mounted. Place your sample face down on the wax and slide the sample a
little bit to get uniform wax thickness with the sample ultimately centered
on the substrate.
5.1.6 Apply pressure and/or weight on the sample if necessary. Weight should
not be used on soft materials e.g., III-V compounds. Place a piece of filter
paper on the sample and gently place the weight on the paper. Turn the
hot plate off and wait for at least 20 minutes.
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5.1.7 Take the substrate off the hotplate. Put it on the table and let it cool
down. Use wiper with Opticlear to clear the wax around the mounted
sample.
5.1.8 Measure the thickness of the sample after mounting. Compared with the
thickness obtained in step 5.1.2, the wax thickness should be noted.
5.2 Slurry Preparation In order to obtain a reasonable lapping rate and acceptable
surface roughness, a proper abrasive slurry sequence should be determined in
advance.
5.2.1 Check the abrasive size left in the cylinder. If the slurry in the cylinder
is the size you want to use, shake it well before you use. Add more
slurry if needed. The total amount of slurry should NEVER exceed
the grooved line on the cylinder, as indicated by the arrow in Fig. 1.
5.2.2 To make a new slurry, open the cap carefully with the screwdriver in the
tool box. Untighten the four screws for the flux controller, as shown in
Fig. 2. To take the valve out of the cylinder, turn the valve head
counterclockwise. Dump the old slurry into the slurry waste bottle.
NEVER DUMP SLURRY DOWN THE SINK. Clean the cylinder,
cap, and valve thoroughly. Put the valve back when done.
5.2.3 Make up Al2O3 abrasive slurry of desired particle size by mixing – ml DI
water and 1.5 cups of powders in a beaker. Stir the solution entirely with
the Teflon boat holder in the fume hood. Pour the slurry into the cylinder
with a funnel. Add more water into cylinder until the level reaches the
grooved line. However, keep slurry volume more than half of the
maximum to obtain constant feeding rate.
5.2.4 Tighten the cap and close the header completely by turning header
clockwise. Then open it by turning it counterclockwise for about one turn.
5.3 System Setup
5.3.1 Check the slurry waste bottle under the machine is less than 90% full.
5.3.2 Verify the vacuum exhaust at the Magnhelic gauge in fume hood is >0.
5.3.3 Clean the jig thoroughly with clean room wipers and alcohol.
NOTE: Always use DI water and wipers to clean plates, slurry chute, jog holder, and
conditioning plates before using them, and always clean them again when switching slurry.
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6.0 PROCEDURE
5.3.4 Put the cylinder on the autofeed stage, making sure that it sits on both
rubber rollers appropriately.
5.3.5 Remove slurry chute, jig holder, and slurry scraper assembly.
5.3.6 Select the proper plate you want to use. The function of the plates is
tabulated below:
Plate Function Sample Materials
Grooved Iron Lapping Si/Glass
Glass Lapping / Polishing GaAs, InP
Stainless Steel w/Pad Polishing/Planarization Oxide/Nitride/Metals
Polyurethane Rough Polshing Silicon/Glass
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NLS-030
5.3.7 Install the plate you choose by matching the three pins of the plate to the
three holes on the plate stage. Be careful to keep your hands always in the
groove, so that you do not pinch your fingers, as shown in Fig. 3.
5.3.8 Install slurry chute, jig holder, and slurry scraper assembly, as seen in Fig.
4. Please note that the wheels of jig holder never touch the plate.
6.1 Conditioning Plate The purpose of this process is to make the lapping plate
smooth, so that the sample can be lapped uniformly. Always use 9 μm or larger
size of Al2O3 slurry for conditioning the plates.
NOTE: Use iron conditioning plate for grooved iron plate; Use grooved iron
conditioning plate for iron plate; Use grooved glass conditioning plate for glass plate.
6.1.1 Turn on the main power of the machine.
6.1.2 Turn on vacuum by flipping the toggle switch on the vacuum pump located
under the machine.
6.1.3 Press “POWER ON/OFF” bottom on the control panel, then press
“START” bottom to rotate the plate. Increase the rotation rate to 3 rpm
by pressing the “4”bottom.
6.1.4 Press “ABRASIVE AUTOFEED ON/OFF” bottom, the slurry will feed
automatically. Adjust the feeding rate by turning the valve on the cylinder
clockwise (decrease) or counterclockwise(increase). Adjust the slurry
feeder, so that the slurry drops at the position of 3 inch away from the
center of the lapping plate.
6.1.5 When the slurry wets about 10% area of the plate, stop the rotation by
pressing “STOP” bottom.

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NLS-030
6.1.6 Place the right “test block” on it very carefully to avoid scratching the
plate. The position of the test block is crucial. Its edge should suspend
out of the plate for about 0.75 inch. Never adjust such that the outer edge
of the conditioning plate is entirely inside the outer outer edge of the
lapping plate. Tight jig holder. Put weight on it carefully, as seen in Fig. 5.
6.1.7. Press “START”, and then the “4” bottom to slowly increase rotation
speed to 2-4 rpm. Check whether the test block and weight are held by the
jig holder smoothly and firmly. If not, take the weight and test block out,
and then adjust the position of the jig holder. Repeat the procedure 3 to 4
to get the right setup.
6.1.8 Increase the speed to 70 rpm(for iron plate, and 50 rpm for glass plate).
Condition the plate for 20 minutes.
6.1.9 When done, press “STOP”. Take the weight and test block off. Clean the
test block by DI wafer and wipers. Dry it by wipers or nitrogen blow dry.
6.1.10 Then use the flatness dial to read the flatness of the test block (see
appendix Ib for the instruction of how to operate the dial). Record the
flatness on the logbook.
6.2 Programming Lapping Thickness
6.2.1 Unplug the recharge power wire for the Digital Micrometer Unit.
6.2.2 Turn on the power to the SAMPLE MONITOR and the Digital
micrometer, DG-925, located in the jig.
6.2.3 Press “SET” on the SAMPLE MONITOR. Use “+” and “−” to enter “the
thickness, in microns, to be removed”. Press “SET” again.
6.3 Sample Lapping
6.3.1 Put the glass substrate with sample facing up on the vacuum chuck of the
jig. Plug the vacuum hose into the vacuum adapter located on the machine.
Check to ensure that the glass substrate is held tightly.
6.3.2 Press “START” bottom to rotate the plate. Increase the rotation rate to 3
rpm by pressing the “4”bottom.
6.3.3 Press the “ABRASIVE AUTOFEED ON/OFF” to feed slurry.
When the slurry wets about 20% area of the plate, stop the rotation by
pressing “STOP” bottom. Make sure that there is enough slurry on the
area where jig sits. If a lot of time has elapsed since the plate condition.
stops, run the condition block for a few minutes.
6.3.4 Hold the 2 nd and 3 rd rings of the jig carefully by your fingers, as shown in
Fig. 6, then flip your wrist and place it on the plate with great caution, as
seen in Fig. 7. Release the second ring of the jig after the jig is securely on
the lapping plate.

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NLS-030
6.3.5 Check if the wheels of the jig holder are in the right position, i.e. match the
first ring of the jig, as seen in Fig. 8. Never move the jig around on the
plate, while the sample is down. Make all needed adjustments while
holding the 2 nd and 3 rd rings together.
6.3.6 Check if the reading on DG-925 is zero. If not, press “RESET”.
If it is still not zero, more weight/pressure may be needed.
6.3.7 If weight/pressure adjustment is needed, use one of your hands lifting up
the second ring, and then use the other hand adjusting the weight by
rotating the big screw, as illustrated in Fig. 9. Always lift up sample when
adjust weight/ pressure. Turn it clockwise to increase weight or
counterclockwise to reduce weight.
6.3.8 Press “START” and then “ABRASIVE AUTOFEED ON/OFF” to feed
slurry. Increase the rotation rate to 2-4 rpm by pressing the “4”bottom.
6.3.9 Turn on slurry sensor to monitor slurry feeding, which locates under the
cylinder head. When the slurry feeding rate is too slow, it will shut down
the machine to protect sample from being destroyed.
6.3.10 Examine the reading on DG-925. If it is stable, press “RUN” on Sample
Monitor. Then increase the speed to 25 - 35 rpm.
6.3.11 Always close the lid during lapping. In particular, for InP, phosphine
comes out during lapping and polishing.
6.3.12 Check the jig position once in a while. The jig may separate from the jig
holder.
6.4 Lapping Completion
6.4.1 The machine shuts down automatically once the set thickness is removed.
Press power off to silence the beeping.
6.4.2 Turn off the digital micrometer and the sample monitor.
6.4.3 Hold the 2 nd and 3 rd rings of the jig by your fingers. Take it out very
carefully. Flip it over and place it on the plastic jig rack on
the table, as shown in Fig. 6.
6.4.4 Unplug the vacuum hose from the adapter. Wait for about 20 seconds.
Then take the glass substrate out.
6.4.5 If no polishing needed, clean the machine and the jig thoroughly.
6.4.6 Turn off the main power for the machine
6.4.7 Turn off the power for pump.

7.0 POLISHING
6.4.8 Label the cylinder with the slurry size and the date made.
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NLS-030
6.4.9 Recharge the battery of the Digital Micrometer Unit by plug in the 9V DC
power adapter.
6.4.10 Fill out the logbook completely.
6.4.11 If silicon carbon or cerium oxide abrasive is used, make a note on the
slurry waste container.
6.4.12 If polishing is required, go to section 7.0. If not, go to Section 9.0
for sample removal.
When a very smooth and reflective surface are required (Ra

7.1.5 Repeat procedures 5.3.1 to 5.3.8 to setup polishing system.
7.1.6 Setting up the Sweeping Arm as follows to achieve better surface
finishing.
7.1.6.1 Press Sweeping Arm button on the LCD screen.
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NLS-030
7.1.6.2 Choose SYSChecks button. The screen should show “System
Checks in Progress”.
7.1.6.3 Press Continue button when the system checks are done.
7.1.6.4 Press Edit button.
7.1.6.5 Set Inner Sweep Limit by using “ + “ and “–“ buttons.
The lower the number is; the wider the arm sweeps.
7.1.6.6 Choose Next button to go to Outer Sweep limit setting. Adjust
range by using “ + “ and “–“ buttons, so that the sample always
stays on lapping plate during sweeping. The higher the number is,
the wider the arm sweeps.
7.1.6.7 Press Next button to go to sweep speed setting. Set the speed to
approximately 70%.
7.1.6.8 Press Exit button to exit the Sweeping Arm setting.
7.1.7 Follow the procedure from 6.3.1 to 6.3.12. Skip procedures for using the
digital micrometer (6.3.6, 6.3.8, and 6.3.9).
7.1.8 Press Sweeping Arm button to start sweeping. Adjust the sweep amplitude
and speed if needed.
7.1.9 Press “Exit” button when the polishing is done.
7.1.10 For the purpose of disposing the slurry waste, make a note on the sheet
attached to the waste container when colloidal silica or Chemlox solution
is used.
7.1.11 Clean the plate and the polishing pad completely. Leave a note on the
polishing plate underside for the materials lapped and polishing solution
used.
7.1.12 Clean the machine and jig thoroughly.
7.1.13 Fill out another record in the logbook for polishing.
7.1.14 Go to Section 9.0 for sample removal.

7.2 Rough Polshing by Polyurethane Plate
8.0 Planarization:
Polyurethane plate with colloidal silica solution can be employed to coarsely
Polish silicon or glass.
7.2.1 Conditioning plate.
Before polishing the plate, the plate needs to be conditioned by the
stainless steel test block with blades.
7.2.1.1 Follow the procedures from 5.3.1 to 5.3.8 to setup polishing
system using the Polyurethane plate with the test block.
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NLS-030
7.2.1.2 Spread water on the plate by a wash bottle. Make sure that the
amount of water is enough to wet all the surface of the plate.
7.2.1.3 Put the test block on the plate, and hold it by jig holder.
7.2.1.4 Spread water on the plate by a bottle. Make sure that water wet
all the surface all the time during the conditioning process.
7.2.1.5 Turn on the main power of the machine.
7.2.1.6 Press “POWER ON/OFF” bottom on the control panel, then
press “START” bottom to rotate the plate. Increase the rotation
rate to 3 rpm by pressing the “4”bottom.
7.2.1.7 Check whether the test block and weight are held by the jig
holder smoothly and firmly. If not, take the weight and test
block out, and then adjust the position of the jig holder
7.2.1.8 Increase the speed to 35 rpm. Condition the plate for 3 to 5
minutes. Spread DI water constantly to keep the surface of the
plate wet.
7.2.1.9 When done, press “STOP”. Take the test block off. Clean the
test block by DI wafer and wipers. Dry it by wipers or nitrogen
blow dry.
7.2.2 Rough Polishing
Use colloidal silica for polishing silicon; while cerium oxide for
polishing glass.
7.2.2.1 Select the proper polishing solution. Follow the procedure in
Section 7.1.

Oxide, nitride, or metals can be planarized by the following procedure:
9.0 SAMPLE REMOVAL
8.1 Use the stainless steel lapping plate with PANMA 12” DP-PAN
polishing cloth.
8.2 Following the procedure in Section 7.1. Use colloidal silica
for planarization.
Samples may be removed either by melting or dissolving method.
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NLS-030
9.1 Melting method When SILICON samples are thicker than 200 μm, the sample
may be taken off the glass plate by melting the wax on a hotplate.
9.1.1 Place glass substrate on the hotplate with sample facing up. Turn the
temperature to 110 set point for white wax ( 160 for black wax).
9.1.2 Wait for about 10 minutes. Use tweezers to push the edge of the sample
to slide it off the glass substrate.
9.1.3 Clean the sample and the substrate by immersing them into the Opticlear
solution stored in the fume hood next to the machine, followed by
alcohol and DI water rinse.
9.2 Dissolving method For brittle materials, such as thinner Si samples, GaAs, or
InP, it is recommended to use the Opticlear solution to dissolve the wax laterally.
9.2.1 Use the beaker labeled “Opticlear” in the fume hood next to the machine.
Place the glass substrate on the teflon ring in the beaker with sample
facing down. Make sure that the sample does not touch the teflon ring.
9.2.2 Make sure that there is enough Opticlear solution, so that the solution
covers the sample. Cover the beaker with a petri-dish lid.
9.2.3 The sample will drop into the solution when done. It will take few to tens
of hours, depending on the sample size.
9.2.4 Clean the sample and glass substrate by alcohol and DI water.

Valve
Cap
Max
Fig. 1 The cylinder
Groove
12
Fig. 2 Cylinder cleaning
Fig. 3 Install a lapping plate on the machine. Fig. 4 System setup.
Weight
Lapping
plate
Condititon
plate
Fig. 5 Conditioning lapping plate.
Cylinder
Slurry feeder
NLS-030
Rubber
Cleaning
pad
Jig holder

Fig. 6 Holding the jig by press the 2 nd
and 3 rd rings together.
Fig. 8
2 nd ring
3 rd ring
Fig. 8 The proper position of the
jig on the lapping plate
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NLS-030
Fig. 7 Placing the jig on the lapping plate
Fig. 9 Adjusting the weight
on sample

APPENDIX I
a. Operation Procedure for Measuring Sample Thickness Using a Dial
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NLS-030
a.1 Lift the tip up carefully by pulling the knob on the dial. Place the glass
substrate with sample on it below the tip, so that when the tip is released, it
lands on glass substrate, not on sample.
a.2 Rotate the outer ring of the dial. Zero the height by matching the outer
indicator to zero.
a.3 Pull the tip up again and move the glass substrate, so that the sample is
below the tip. Release the tip very slowly and carefully. Read the outer
scale for thickness of the sample. The smallest unit in the outer scale
represents ten microns.
b. Operation Procedure for Measuring Surface Flatness of a Conditioned Lapping
Plate.
b.1 Move the flatness dial slightly around the flat standard to seat the tip. Zero
the dial if needed.
b.2 Place the test block up side down on the weight.
b.3 Use one finger to raise the tip by lightly pressing the handle above the
dial before taking the dial off the standard. Take it off from the standard.
Place it on the conditioned plate. Release the handle very carefully until
the probe touches the plate. Move it around and read the flatness. The
smallest scale on the dial is two microns. The smallest scale on the outer
dial is two microns.