The Headway Coater is used to apply photoresist to any substrate. Centrifugal force uniformly spreads fluid across the surface of the spinning substrate. The spin speed, spin time, and substrate and fluid properties determine the final thickness of the film.
Contents
Contact List and How to Become a User
Training to Become a Tool User
Coating/Spinning after programming Headway 3 controller
Picture and Location
This tool is located in L107 (Stinson) room in ExFab, in the Wbexfab_solv bench.
Process Capabilities
Cleanliness Standard
The headway 3 appears in all three cleanliness groups (clean, semiclean, and flexible).
Performance of the Tool
What the Tool CAN do
- Allow manual dispensing of any SNF-acceptable photoresist
- Adjustable spin speeds and spin time
- Interchangeable vacuum chuck allows processing of wafer chips and substrates of unusual size or shape
Contact List and How to Become a User
Contact List
- Process Staff: Swaroop Kommera
- Maintenance: Gary Sosa
Training to Become a Tool User
- "All Litho" is required before training on any of the lithography tools. Contact the trainers for the class schedule and training materials (which must be reviewed before the class).
- Contact Swaroop Kommera for training. Please review the materials before training.
Operating Procedures
Overview
- For procedures on manual coating, click <here>. This is specific to Headway2, but the general principles apply to Headway3.
- For procedure for manual developing, click <here>.
- You can manual resist coat the following resists
- Shipley 3612
- SPR220-3/7
- Any approved non-standard resists, polymers.
Special Notes or Restrictions
- Faceshield is mandatory to be used as a PPE for spinning your samples on Headway3. Faceshields are located on both sides, on the outside of Wbexfab_dev wet bench. Please use them and return them to their original position
- Please make sure to check vacuum for every wafer. This is an important check.
- Pieces to 6 inch wafers
- Check the MSDS sheets for hazard information on the photo-resist you are using and handle them with caution.
- Please spin only approved resists or materials in Headway3. If you need to spin a new chemical, please fill out a PROM request. If you have any questions regarding whether a resist/material is approved or not, please contact Swaroop Kommera
- Keep open containers at least 6 inches back from the front of the exhaust hood
- Notify the staff immediately if resist smells are detected while working at the station.
- You can only perform approved processes on this bench. If you need to do a new procedure/process, please get it approved with Swaroop first. Doing unauthorized procedures at this bench can lead to deactivation of your account on the wet bench and potentially the SNF.
Handling Personal Chemicals
Here is the short version for handling personal chemicals after SNF approval:
- Get a yellow label (for personal chemicals).
- Make sure you have all the information including the date filled in. If there is no date, we will dispose the chemical during shut down (no warning issued).
- All non-standard chemicals should to be stored in the yellow flammable cabinet in the service area (behind furnaces) or in the yellow flammable cabinet near Headway3 (there is a limited amount of space).
- If you want to keep the chemical, get a new label with new date before shut down, otherwise will dispose during shut down (no warning issued).
Basic Operation Instructions
Initial Checks
- Enable "headway 3"
Before Coating
- Program the Headway controller. The information to program is listed below.
SEQUENCE PROGRAMMING OF THE PWM32 CONTROL UNIT ON HEADWAY
Process Contact: Swaroop Kommera
Maintenance Contact: Gary Sosa
Basic Things to Understand Before Programming
1) A sequence of events (steps) combine to define a process (recipe).
2) A recipe is identified by a number 0 through 9. (10 possible).
3) A step within a recipe is identified by a number 1 through 9. (9 possible).
4) The system can be in one of 5 states. Each of these states is clearly displayed by word or action on the LCD display:
· READY (to run a recipe) or
· RUNNING (a recipe) or
· REVIEWING (a recipe) or
· PROGRAMMING (a recipe) or
· ABORT (a running program)
The START switch becomes the RESET switch to return to READY, from the abort state. To return to READY, from REVIEWING OR PROGRAMMING, press STEP and then 0, in sequence.
5) The currently selected recipe number is shown in the upper left-hand corner of the LCD display. Recipes are selected (in the READY state only) by pressing the function key labeled RECIPE, and then pressing the number of the recipe desired. The selected recipe number will be written to the LCD.
6) Below the recipe number in the LCD display, the active step (when a program is running) and number of the last step of the recipe is displayed, example: 2-6 means the process is in the second (2) step of a sixth (6) step process. If the process has not yet been started, then only the number of the last (highest) step of the recipe is shown.
7) Every step has a timer that can be set by the process programmer. If this timer times out, it will terminate the step. It can be set anywhere between zero and 999.9 seconds. A step can be temporarily skipped by setting the timer to zero. The time remaining in the currently running step is always displayed in the field of the LCD marked TIME.
8) Once programmed, a single step cannot be erased or eliminated. It can be skipped by setting its timer to zero or all steps of a recipe can be simultaneously erased by pressing the function keys RECIPE then CLEAR then (Recipe #). The highest step in the recipe becomes zero (0). Once all steps of a recipe have been erased the recipe can be reprogrammed as desired.
9) Vacuum to the chuck/substrate can be managed automatically by the system or can be forced to stay on by the operator. The vacuum ON/AUTO function key is a toggle. A two character field at the left of the LCD displays the current status: ON = Manually ON, AU = Automatic.
10) A rotation sensor on the motor forces the vacuum to be turned on if the motor is spinning, overriding all other control of the vacuum. This ensures that the vacuum will continue holding the substrate to the chuck until the spinner comes to a complete stop.
11) If a recipe is running in a step, that STEP can be immediately terminated by the operator pressing the function key labeled OFF or CLEAR. It is also possible on any or all steps to program the START switch as a step terminator. WARNING!! The operator MUST be aware of what could happen if a step is skipped without its normal programmed termination. This will be unique to the user-programmed activities. The user should be prepared to quickly ABORT the entire sequence if something unexpected occurs when a step is skipped prematurely.
12) The START/ABORT switch is a dual, center-balanced, rocker footswitch. The side with the green circle is the start switch, the side with the red circle is the abort.
13) If a process is aborted, the START switch becomes the RESET switch, to return to READY.
14) While a recipe is running, the speed of the spinner may be increased or decreased manually by pressing the STEP TERMINATE (increases speed), or SYSTEM PARAMETERS (decreases speed). This manual speed change is temporary, it does not change the speed set in the program. Please make sure you are aware of the consequences when you use this function.
15) The step timer does not start timing until the speed for that step is reached. Thus the total time for the step will be the sum of the acceleration (or deceleration) plus the time setting of the timer. A slow ramp setting can significantly affect the total step time.
Programming
1) Layout your program before programming the Headway 3. Keep the program schedule handy so you can quickly recognize which step you need to go into to modify some parameter such as speed, acceleration, spin time, etc.
2) Decide the Recipe Number you wish to use to store the program and select it (in the READY state only) by pressing the function key labeled RECIPE and then the desired number on the 10-key pad (0-9). If this recipe already has a program, you may modify the existing steps and add new steps as desired to get the program you want. If you want to reduce the number of steps or prefer to start with a clean slate, then you must erase the entire recipe by pressing the function keys labeled RECIPE then CLEAR and then the Recipe # (in the READY state only). The recipe # entered will then show to be a recipe with zero (0) steps. It can now be reprogrammed.
3) Select Step 1, by pressing the function key labeled STEP, and then pressing 1 on the 10-key pad. Note that the highest numbered step, 0, has changed to 1 on the LCD.
1) Press the function key labeled SPEED/RAMP. Enter the desired speed and verify it as displayed in the LCD. (Must press the ON or ENTER key to accept the number keyed in for the speed or ramp.) The SPEED/RAMP key is a toggle.
2) Press the SPEED/RAMP key again. Enter the desired acceleration/deceleration (ramp) for this step, and verify it as displayed in the LCD. (Press ON or ENTER to accept the entry.)
NOTE: When entering numbers, the OFF or CLEAR key will act as a backspace key to allow correcting an entry prior to pressing the ON or ENTER key.
3) Set the step terminator(s): Something must happen to cause a step to end (terminate) and the sequence to move on to the next step. Most commonly the step terminator will be time as set on the step timer.
If a process calls for an event to take more than 999.9 seconds, then it will be necessary to series two or more sequential steps with the same process conditions to obtain the longer time desired. When all of the parameters of step 1 are as desired, select the next higher step for programming.
4) Select Step 2 By Pressing, STEP, then 2: Proceed with setting the desired speed, ramp, functions and step terminator as in programming step 1. Proceed until all desired steps are programmed. When all steps have been programmed, terminate the recipe by pressing the function key labeled STEP, and then the number zero (0) on the 10-key pad. This will return you to the READY state.
5) A recipe may be reviewed or modified by pressing STEP and the step number to be reviewed or modified (when in the READY state). This will put you in the REVIEW state. Once anything is changed in the recipe, the ‘REVIEWING’ mode automatically changes to ‘PROGRAMMING’ mode. Reviewing or programming is terminated by pressing the STEP and 0 buttons, sequentially. Pressing STEP and 0 buttons sequentially will return the system to the READY state from either the REVIEWING or PROGRAMMING mode.
One item to note: When the last step of a recipe terminates, the spinner will decelerate to zero speed at its maximum deceleration rate. This may not be desirable when using Inhibited Drying Spinning (IDS) techniques. An additional step of programming can be used at the end of the cycle to bring the spinner to zero speed at a more satisfactory deceleration rate. Just add one more step to the recipe and make the speed = zero, the timer = zero, and set the ramp to a satisfactory rate. The “stable speed” feature prevents the step timer from starting until the speed set in the step has been reached at the set ramp rate. Therefore the spinner will decelerate at the desired rate until it reaches zero, then the step timer will instantaneously terminate the step and the objective has been achieved.
Coating/Spinning after programming Headway 3 controller
- Select the appropriate chuck. Make sure it is clean and has an O-ring on the inside. Check the Delrin insert. Choose the correct size chuck for your wafers. The chuck size should be smaller than the wafer size.
- Vacuum check the system with the selected chuck and dummy wafer - Center a wafer and check vacuum by pushing the "Vacuum On/Auto" button and physically checking the vacuum on the wafer. After checking, press the "Vacuum On/Auto" button so that the Vacuum is set to Auto. You should check vacuum on every process wafer as well.
- Apply photoresist to your wafer. Step on the front of the pedal to start the spin. The START/ABORT switch is a dual, center-balanced, rocker footswitch. The side with the green circle is the start switch, the side with the red circle is the abort. If a process is aborted, the START switch becomes the RESET switch, to return to READY. While a recipe is running, the speed of the spinner may be increased or decreased manually by pressing the STEP TERMINATE (increases speed), or SYSTEM PARAMETERS (decreases speed). This manual speed change is temporary, it does not change the speed set in the program.
- Coating tips: If you notice some areas near the edge do not get covered with resist, it may be necessary to increase the time (typically 30 seconds) to 40 seconds and after applying the resist, you may need to spin the wafer/substrate at a slower speed to spread the resist uniformly. Let the resist spread across the wafer and in the next step increase the speed to the correct setting.
- Could be simply you are not applying enough resist.
- Please do not pour back any of the resist from beaker to the main bottle, this will contaminate the whole bottle.
- All the standard resists are kept in the yellow flammable cabinet next to the bench.
The flammable cabinet in the exfab area (next to the wbexfab_solv bench) will only be for standard small bottles and spray coater resists. There is limited space for personal bottles should be stored at any time in the yellow cabinet next to headway. We strongly suggest that everyone follow the policy as we will dispose of any personal chemicals left in there. (No warning or email be issued).
Clean Up
- Always dispose of solvent contaminated items properly. Never bring solvent contaminated items out from under an exhaust hood unless they are in a closed zip-log bags ( your gloves can be used for small items). If your glove is contaminated (i.e. with photo-resist) turn it inside out to prevent fumes and touching the surface of the bench. Transfer all the contaminated items like, foil, wipes, gloves and q-tips to zip-log bag and dispose it in to hazardous bin next to wbexfab_corr.
- Disable "headway 3"
You should find the tool clean before use and leave it clean for next user, please note all the issues on Badger.