Spin-on Dopant (SOD)

Application and Pre-bake

Standard Operating Procedure

February 24, 2013

By: Matt Staniszewski

PI: Bruce Darling

Electrical Engineering

Contents

Table of Figures ................................................................................................................................................. 3

List of Chemicals ................................................................................................................................................ 4

Hazards .......................................................................................................................................................... 4

2-Methoxyethanol ..................................................................................................................................... 4

Reagent Alcohol ......................................................................................................................................... 4

Personal Protective Equipment .......................................................................................................................... 5

Procedure .......................................................................................................................................................... 5

Prepare SOD .................................................................................................................................................. 5

Set Up Hot Plates ........................................................................................................................................... 5

Set Up Headway Spinner ................................................................................................................................ 8

Configure settings ........................................................................................................................................ 11

Choose the correct recipe ........................................................................................................................ 11

Customize Recipe ..................................................................................................................................... 12

Testing Spinner Settings ............................................................................................................................... 12

Apply SOD .................................................................................................................................................... 12

Run Spinner ................................................................................................................................................. 14

Pre-bake ...................................................................................................................................................... 14

Cleanup ....................................................................................................................................................... 14

Spill & Accident Procedures ............................................................................................................................. 15

Waste Disposal ................................................................................................................................................ 15

Special Procedures for Animal Use ................................................................................................................... 15

Particularly Hazardous Substances ................................................................................................................... 15

Approval Required ....................................................................................................................................... 15

Decontamination ......................................................................................................................................... 15

Designated Area ........................................................................................................................................... 16

Additional Information ..................................................................................................................................... 16

Table of Figures

Figure 1 - B155 (background) and P509 (foreground) spin-on-dopant ................................................................ 5

Figure 2 - Hot plate bench .................................................................................................................................. 6

Figure 3 - Location of aluminum foil next to the Headway spinner ..................................................................... 6

Figure 4 - Foil wrapping around two of the hot plates ........................................................................................ 7

Figure 5 - Dataplate Hot Plate ............................................................................................................................ 7

Figure 6 - Thermo Hot Plate ............................................................................................................................... 8

Figure 7 - Headway spinner in Coral ................................................................................................................... 8

Figure 8 - Headway spinner ................................................................................................................................ 9

Figure 9 - Headway spinner final assembly ......................................................................................................... 9

Figure 10 - Foot pedal for Headway spinner ..................................................................................................... 10

Figure 11 - Flat of Headway spinner ................................................................................................................. 10

Figure 12 - Location of vacuum pump and power switch (circled)..................................................................... 11

Figure 13 - Headway controller front panel ...................................................................................................... 11

Figure 14 - Location of the reusable pipette tops next to the green disposable pipette bottoms (circled) ......... 13

Figure 15 - Location of clear disposable pipettes next to the Headway spinner (circled) ................................... 13

Figure 16 - Location of the green pipette bottoms next to the controller (circled) ............................................ 13

List of Chemicals

This SOP was written based on the Filmtronics B155 polyboron and P509 phosphorus SODs, whose chemical

compositions are proprietary. However, their primary solvent properties are the following:

• B155: 2-Methoxyethanol, 80-99% volatile by volume – CAS #109-86-4

• P509: Reagent Alcohol, 60-99% volatile by volume – CAS #64-17-5

Please consult the MSDS for your SOD for corresponding information and hazards. There are no chemicals

associated with the spinner or hot plates other than cleaning solvents such as isopropanol alcohol (IPA) and

acetone, which have their own corresponding SOPs.

Hazards

Avoid skin or eye contact with SODs and keep it off your clothing. Do not ingest or breathe SOD vapor or mist.

Keep away from open flames or sparks as SOD can be highly flammable.

2-Methoxyethanol

• Inhalation – Vapors are irritating to nose, eyes and respiratory tract. Can cause upper respiratory

congestion, fatigue, nausea, vomiting, dizziness, stupor and coma. If overexposed, remove to fresh air;

if not breathing, perform mouth-to-mouth respiration. Seek medical attention immediately. Long term

exposure might aggravate existing respiratory or cardiovascular conditions.

• Ingestion – Give victim 2 – 4 cupfuls of water or milk if they’re still conscious. Never give an

unconscious person anything by mouth. Induce vomiting using one teaspoon of ipecac and seek

medical attention.

• Skin and Eyes – Wash affected skin area with soap and water. Remove and wash contaminated

clothing and seek medical attention if irritation persists. For eyes, immediately flush with water for 15

minutes, lifting both eyelids. Seek medical attention and evaluation.

• Toxicity – See Reproductive hazard below.

• Targeted Organs – May harm liver and kidneys. See Reproductive hazard below

• Reproductive hazard – May cause infertility or harm to unborn child if overexposed. Studies have

shown that this material causes birth defects, fetotoxicity, embryolethality, anemia, bone marrow

damage, hemolysis, immune-suppression and damage to male reproductive tissues.

Reagent Alcohol

• Inhalation – May cause severe burns. Can cause dermatitis, upper respiratory congestion, fatigue,

nausea, vomiting, dizziness, stupor and coma. If overexposed, remove to fresh air; if not breathing,

perform mouth-to-mouth respiration. Seek medical attention immediately. Long term exposure might

aggravate existing respiratory or cardiovascular conditions.

• Ingestion – Give victim 2 – 4 cupfuls of water or milk if they’re still conscious. Never give an

unconscious person anything by mouth. Induce vomiting using one teaspoon of ipecac and seek

medical attention.

• Skin and Eyes – Wash affected skin area with soap and water. Remove and wash contaminated

clothing and seek medical attention if irritation persists. For eyes, causes severe irritation.

Immediately flush eyes with water for 15 minutes, lifting both eyelids. Seek medical attention and

evaluation.

• Toxicity – See Reproductive hazard below.

• Targeted Organs – May harm liver, kidneys and central nervous system. See Reproductive hazard

below

• Reproductive hazard – May cause reproductive and fetal effects.

For more information, please consult the MSDS’s listed in Additional Information below.

Personal Protective Equipment

When working with SODs, it is recommended that you wear standard cleanroom equipment as specified in the

MFF Lab User Manual, including nitrile gloves and safety glasses or goggles. Since all work with SODs at the

MFF is done under a fume hood, no respirator is needed.

Procedure

Prepare SOD

• Please read the MSDS for your SOD prior to use.

o This SOP was written based on the Filmtronics B155 and P509 SODs, whose MSDS’s are provided in

the Additional Information section at the end of this document

• Follow instructions for the SOD regarding storage and preparation

o Store SODs in a well-ventilated area away from sun, heat and ignition sources. Refer to your SOD’s

storage instructions for the proper storage temperature.

o Always check expiration dates of the SOD, which are printed on the bottle.

• Be sure to label SOD with your name

• Many SODs must be left out at room temperature after refrigeration to obtain the proper viscosity.

Figure 1 - B155 (background) and P509 (foreground) spin-on-dopant

Set Up Hot Plates

1. Locate the hot plate(s) at hood labeled “HOOD3-noHF” in the photolithography room.

Figure 2 - Hot plate bench

2. Determine the number of hot plates you are going to use; each hot plate can hold about four 4”

(100mm) wafers.

3. Ensure that the hot plates are currently not running by verifying temperature on front readout is in the

room temperature range (about 15-20 °C) or is off.

a. You can also place your hand above the hot plate surface to verify that hot plate is off.

4. Obtain aluminum foil from the container next to the wipes to the right of the Headway spinner and

tear off a clean, wrinkle-free sheet big enough to cover the hot plate surface.

a. SOD is a messy substance, so it is important to protect the hot plate surface

Figure 3 - Location of aluminum foil next to the Headway spinner

5. Place foil on the hot plate surface, wrapping the edges under the lip of the hot plate top, ensuring that

the foil surface remains smooth and flat to prevent uneven wafer heating.

Figure 4 - Foil wrapping around two of the hot plates

6. Set the temperature of the hot plate

a. Dataplate Hot Plate

Figure 5 - Dataplate Hot Plate

i. Press the “SET” button and wait one second for the display to zero out (shows all L’s)

ii. Enter the temperature by pressing the corresponding numbers on the front panel

iii. Press “SET” button again to set the temperature

iv. The display will alternate between the current and set temperature while it heats up.

b. Thermo Hot Plate

Figure 6 - Thermo Hot Plate

i. Turn the knob on the hot plate until the display turns on

ii. Push the knob in to set the temperature

iii. Turn the knob until reach desired temperature

iv. Push the knob again to set the temperature

v. The display will show the current temperature while it heats up.

Set Up Headway Spinner

1. Log on to Coral and activate the Headway Spinner

Figure 7 - Headway spinner in Coral

2. Locate the Headway spinner, which is located under the hood labeled “SPIN5-HEADWAY” in the

photolithography room.

Figure 8 - Headway spinner

3. Verify that the spinner bowl has been cleaned and the following components are installed properly

a. Base bowl and two drains

b. Drain tile with holes around edge for drainage

c. Headway panel with four pins that mount to inner frame

d. Teflon shield to drain resist or SOD towards drain tile

Figure 9 - Headway spinner final assembly

4. Verify that the controller to the right of the spinner hood reads “READY”

a. If not, hit the red button on the foot pedal next to the spinner to cancel the current recipe

Figure 10 - Foot pedal for Headway spinner

b. The left-hand column should display a vacuum of “AU” for automatic

5. Select and Install the correct chuck

a. Teflon chucks are available for 3” and 4” wafers; a stainless steel chuck is available for smaller

pieces.

b. Ensure that the entire wafer covers the entire chuck surface!

c. Ensure that the flat of the chuck is aligned with flat of spinner and seated properly

Figure 11 - Flat of Headway spinner

6. Turn on the vacuum pump by turning the switch on that is between the Headway spinner and

controller. You should hear the pump start.

Figure 12 - Location of vacuum pump and power switch (circled)

7. Obtain a pair of wafer tweezers

8. Place a piece of paper towel in front of the spinner bowl and place tweezers on the paper towel

9. Using the tweezers, place the wafer on center of chuck

a. Since there are no alignment pins, you will need to align manually and visually inspect the

spinning wafer.

b. It is not necessary for the wafer to be perfectly aligned; slightly offset wafers don't cause a

problem

c. Do not place your head under hood while aligning

10. Once aligned, apply vacuum by pressing the “VACUUM ON/AUTO” button on the controller

a. Do not apply any SOD at this time!

Configure settings

Choose the correct recipe

Figure 13 - Headway controller front panel

1. Press “RECIPE” on the controller and enter a number (1-9) to choose a recipe

a. Recipes 1-4 are reserved while 5-9 are free to customize

2. For more information about customizing a recipe, see Customize Recipe below, otherwise skip to

Testing Spinner Settings

Customize Recipe

1. To start a new custom recipe, delete an existing one by selecting “RECIPE” and “CLEAR” simultaneously

followed by the number to clear the recipe.

2. Choose the recipe you wish to edit; make sure its number appears in the left-hand column

a. A display next to “Step →” displays the steps as 'X – Y', where X is the current step and Y is the

number of steps in the recipe.

b. A new recipe will only have one step; a typical recipe has three steps (spread, spin, decelerate)

3. To edit a step, press “STEP” followed by the appropriate number.

4. Press “RAMP/RATE”, enter a spin speed in rpm and press “ENTER”

5. Press “RAMP/RATE” again, enter a ramp rate in rpm/s and press “ENTER”

6. Press “STEP TERMINATE” , enter a step time in seconds and press “ENTER”

a. Note that a step time of zero seconds means the step will immediately by skipped

7. To enter additional steps, return to Step 3 above.

8. When finished entering steps, press “STEP” followed by “0” to return to the main screen.

a. The Headway spinner will stop without decelerating automatically if a step is not programmed

in, which can lead to poor SOD uniformity. Be sure to add a deceleration step and give it a step

time in your recipe.

b. The time entered in Step 6 does not include acceleration time.

c. Please talk to MFF staff if using spinner speeds above 7500 rpm.

Testing Spinner Settings

1. Test that the vacuum has worked correctly by applying light pressure to edge of wafer with tweezers to

ensure it doesn't move.

2. Press the green button on the foot pedal next to the station to start the recipe. The spinner will run

the recipe, stop and release the chuck vacuum when done.

o If wafer is not properly aligned, stop the recipe by pressing the red emergency stop button on the

foot pedal; this will emit a large beep and immediately stop Headway operation.

3. To realign, press the green button again and disable the vacuum using the “VACUUM ON/AUTO”

button to allow wafer to be moved with tweezers.

4. Once you find a good align, proceed to Apply SOD section below.

Apply SOD

1. Apply vacuum to wafer with the “VACUUM ON/AUTO” button

2. Use the nitrogen gun at the station to remove any dust particles from the wafer surface

3. Obtain a reusable pipette top from tray to the right of the tray holding the wipes and green disposable

pipette bottoms or use a clear disposable pipette located immediately to the right of the Headway

spinner.

o If using a reusable pipette top, obtain a green disposable pipette bottom from the same tray

located to the right of the controller under the wipes.

Figure 14 - Location of the reusable pipette tops next to the green disposable pipette bottoms (circled)

Figure 15 - Location of clear disposable pipettes next to the Headway spinner (circled)

Figure 16 - Location of the green pipette bottoms next to the controller (circled)

4. Use nitrogen to clean either the inside and outside of the green pipette bottom or clear pipette,

blowing particles away from the Headway hood

5. Attach the green pipette bottom to reusable top if using

6. Unscrew the cap on the SOD bottle place to the side

7. Press down on white plunger or clear bubble of pipette before placing it into the SOD bottle

8. Slowly release plunger or bubble to suck SOD into the pipette

9. Remove the pipette from the SOD bottle slowly and wipe off any excess SOD on the outside

o Be careful of high viscosity SODs, which can easily drip on the wafer and other surfaces

10. Position pipette over spinner bowl away from wafer. Squirt some SOD out of the pipette to ensure

there are no bubbles trapped

11. Position pipette over the center of the wafer and apply pressure to plunger or bubble to release SOD

12. Create a circle of SOD in the center of the wafer that coats about half of the surface.

o If more SOD is needed, repeat steps 7 – 12 to apply more SOD to the wafer.

13. When finished, be sure all SOD is removed from the pipette. Release any excess SOD from the pipette

into the bowl, away from the wafer. Clean the tip and place pipette on towel in front of spinner.

Run Spinner

1. Press the green button to begin the Headway spinner

2. When finished, verify that controller has released chuck vacuum automatically by verifying that vacuum

gauge at the back of the controller reads zero.

3. You can manually release the vacuum by pressing the “VACUUM ON/AUTO” button

4. Use one or two pair of tweezers to carefully remove the wafer from the chuck

5. Place wafer in carrier or other proper holder to transport to hot plate.

Pre-bake

1. Proceed with wafer to the hood labeled “HOOD3-noHF” in the photolithography room where the hot

plates are located

2. Verify that the hot plate has reached the temperature you specified earlier on the display

3. Use tweezers to place wafer from the carrier on to the hot plate surface, with the active side facing

upwards

4. Start timer for pre-bake time based on your recipe.

5. When finished, remove wafer with tweezers and place back in carrier to cool

Cleanup

1. Turn off the vacuum pump by turning off the switch to the left on the Headway controller

2. Disable the Headway spinner and log off of Coral

3. Turn off hotplates and allow them to cool down to room temperature.

4. Using the appropriate solvent for the given SOD as specified in its specification, remove the following

components from the Headway spinner and clean at the solvent bench

o Wafer chuck

o Teflon shield

o Top panel with Headway logo

o Drain tile

5. Clean the non-removable bottom drain as well at the Headway spinner.

6. Reassemble the bowl as shown in Figure 9.

7. Remove and discard aluminum foil.

8. After leaving the cleanroom, wash your hands thoroughly.

Spill & Accident Procedures

If a large SOD spill occurs, isolate the area and evacuate staff that is present in the surrounding area. Remove

all possible ignition sources from the area and provide adequate ventilation and PPE for those working on the

spill. Soak up the spill with vermiculate or another inert material, collect it in a waste container, close it tightly

and dispose of the waste as outlined in Waste Disposal below.

For minor spills and clean up from the process, discard soiled wipes in the red ventilated solvents trashcan to

the left of the Headway spinner.

Waste Disposal

Many SODs are considered hazardous material. Large amounts of waste should be disposed of via incineration

in an EPA-approved facility to create an inert solid residue.

For minor spills and clean up from the process, discard soiled wipes in the red ventilated solvents trashcan to

the left of the Headway spinner.

Special Procedures for Animal Use

Not applicable for this process.

Particularly Hazardous Substances

According the University of Washington's Environmental Health and Safety (EH&S) Lab Safety Manual (LSM),

the chemical substances contained within the example SODs used in this SOP (Filmtronics B155 and P509) are

classified as particularly hazardous substances for being reproductive toxicants. As such, the following

subsections have been included as required.

Approval Required

All chemicals that are currently used in the MFF and have a MSDS filed are approved use within the facility.

For new chemicals, such as a new SOD, please consult Section 10.5 of the MFF Lab User Manual for the process

of getting new chemicals approved.

Decontamination

Please see Cleanup for procedures on cleaning off SOD from equipment. For any accidents, please see Spill &

Accident Procedures for more information.

Designated Area

SOD usage is allowed in the photolithography room of the MFF at benches where SOD spinning and use is

approved, such as the SPIN5-Headway hood where the Headway spinner is located and the SPIN3-noHF hood

where the hot plates are located.

Additional Information

Please see the following resources for more information regarding the SOD and pre-bake process:

• Filmtronics B155 Polyboron Spin-on Dopant MSDS

• Filmtronics P509 Phosphorus Spin-on Dopant MSDS

• SPIN5-Headway Guide – MFF Coral System

• http://www.engr.washington.edu/sites/engr.washington.edu/files/facresearch/microfab/docs/labuser

manual.pdf