Transcript
Operating instructions for MA6 mask aligner
Start procedure: 1. Check whether the lamp is on. If not, please talk to Mikhail Gaevski, Pat Watson or Joe Palmer. Incorrect procedures to light the lamp might cause the explosion of the lamp. 2. If the mask aligner is turned off for any reason, turn on the TV monitor before you turn on the MA6 aligner, because turning on the monitor may generate huge electric surge that damages the delicate circuit of the aligner. If the monitor is off while the aligner is on, you may turn off the aligner first and then turn on the monitor. 3. Turn the power switch on the upper panel to ON if the aligner is not on when you arrive. Wait for the instructions shown on the LCD display, and press the flashing key "load" 4. Choose the lamp operation mode: CI1 or CI2. 2 2 Constant intensity is set at 2.0 mW/cm for CI1 and 3.5 mW/cm for CI2. Although the intensity is not supposed to be changed to ensure the consistency of your recipe and all other users recipes, it can be checked by "lamp test". (Press "lamp test" again to terminate.) 5. Press "select program" to select among different exposure modes. The contact pressure
Rough focus
Microscope
Wafer chuck
Mask holder Stage X, Y, rotation knobs
Microscope monitor Brightness, focus, pressure controls Alignment and exposure controls Lamp power supply with CI1, CI2 selection
(WEC) in soft contact mode is controlled by the knob underneath the WEC pressure gauge. It is
recommended to set it at 0.2 bar to avoid the fracture of your substrate. In the hard contact mode the vacuum securing the sample on the chuck is removed, and nitrogen is introduced under the sample. The nitrogen pressure increases the force which presses the sample against the mask. Proximity contact reduces the damage to the mask by leaving a small gap between the substrate and the mask when exposing. As a result, features smaller than 10 microns would not be resolved accurately. In the vacuum or low vacuum mode, the space between the substrate and mask is evacuated, creating the most intimate contact that leads to the highest precision in the pattern transfer. Load mask and substrate: 1. If MA6 is not already in the "change mask" mode, press "change mask". Pull the mask holder out carefully if it is clamped in the aligner and put it on the left compartment. 2. Choose the appropriate mask holder. Plug in the vacuum hose. 3. Put the mask on the holder, clamp the mask using the clip, and press "enter" to turn on the vacuum. 4. Slide in the mask holder, and press "change mask". The body of the microscope moves down and the mask is now ready in its position. 5. To load the wafer, press "load" and pull the wafer loading chuck out. Regardless of the size of your sample, always place it into the center of the chuck and make sure that it covers all open vacuum holes. Change substrate chuck, if needed. (By choosing the appropriate substrate 2 chuck you may load samples as small as 1 cm .) Press “enter” to turn on the vacuum. If your sample does not cover all vacuum holes, MA6 will report “a loss of vacuum”. Press “enter” to acknowledge that and proceed without vacuum. 6. Slide the chuck back. Press "enter" again to confirm.
Exposure
Mask change Parameters editing
Microscope positioning, parameter selection Alignment check
Program selection
Alignment: 1. Focus. Two knobs under "top substrate" on the lower panel are for fine focusing. The big 2" aluminum knob on top of the microscope body is for coarse focusing. 2. The positions of the objectives can be adjusted with the key X(left), X(right), Y(up), Y(down). Pressing the "fast" key with the previous keys makes movement faster. The distance between objectives can be adjusted by the two 1"-long aluminum knobs on the side of the microscope housing. If your sample is small, choose which objective you would like to use and move it to the center. 3. The gap (Z value) between the substrate and the mask needed for alignment can be adjusted by the key SEP(up) and SEP(down). The gap can also be set by "Al. Gap" in "edit parameter". To change "Al. Gap", press "edit parameter", and use the X-arrow key to select and the Y-arrow key to change. "Fast"+"Y-arrow" enables changing with larger steps. Pressing and holding the Y-arrow key makes the parameter go faster, too.
Stage Y Stage X Sample vacuum selector
Rotation
Mask vacuum 4. Align the substrate to the mask using the three knobs (X, Y, and rotation). When properly aligned, press "alignment check" to bring the substrate in to contact. (contact mode was chosen in previous steps.) Reference points can be stored thus the stage will automatically drive between them allowing the alignment to be checked at different locations. A capturing option is provided to further improve alignment accuracy at the high magnification. Using this options one can, first, focus on the mask, capture the image of the mask, and then, second, switch focus to the substrate surface and align the substrate fiducials to the virtual mask fiducials on the stored image. Exposure and unloading: 1. Set exposure time by pressing "edit parameter" and arrow keys. "Fast"+"arrow key" enables changing with large steps. Pressing and holding the Y-arrow key makes the parameter go faster, too. Repetitively pressing the arrow keys will only reduce the lifetime of the machine, and will not save your time. 2. Press "exposure" to bring the wafer into contact (if not in contact already) and expose.
Main power switch
LCD display
Left/ right microscope, split field
Brightness
Fine focus
WEC pressure
3. Wait until the exposure is done, follow the instructions on LCD display. 4. Pull the wafer loading chuck out completely and unload your sample. (If for any reason you need to unload the wafer before the exposure, press “unload” to pull the chuck out.) 5. If you need to change the mask, press "change mask" and follow the instruction on the LCD display. When done, you must: 1. Put the mask holder back. 2. Leave MA6 and the TV monitor on. 3. Sign the log book.
Thank you for following the instructions to help maintain the facility at its best condition! If you have any questions, please do not hesitate to ask Mikhail Gaevski.
