1. Turning on the Light and Preparations Before Turning on the Light
Confirm the usage status and switch the light path (if the last experiment was at the STXM beamline): In the Motion control interface, open the Mirror-1 control interface, click Home under the X motion option, at this point, the control permission switches to XIL use mode; to switch to STXM use mode, click Offline under the X motion option.
Set the Position value under the Mirror-1 X motion option to 240 and press the enter key to confirm the input.
Change the EPU gap value according to the experimental requirements; under EUV-IL conditions, the gap is 37.47; for 140 eV deep lithography mode, the gap is 44.2.
Adjust the Slit-1 opening to the appropriate XIL lighting setting value (refer to the most recent record in the experimental logbook).
Close V3, open V10, make sure the FS2 status is up, FS3 status is down; the gold target is down, and both vacuum gauges on the experiment station control cabinet are turned on.
Open the shutter and wait for the light path to stabilize.
2. Sample Preparation
The sample should be coated with photoresist and, after pre-baking, it can proceed to section
3. Venting the Exposure Chamber
3.1 Ensure that V11, V12, V13, V15, V16, V18, CCD software (Andor SOLIS), and vacuum gauge (Gauge g8) are all in the closed state. If any components are not closed, ensure that the closing sequence is as follows:
CCD software → V12 → V15 → V16 → V11 → V13 → V18 → vacuum gauge;
Note: The opening and closing of V* valves are operated through the control panel touchscreen. Press the relevant button for 2 seconds until the indicator state shows the corresponding status, such as OPEN for on and CLOSE for off; the CCD software is turned off by clicking the lower left corner of the software interface, indicated as OFF; to turn on the vacuum gauge, press the C.C.ON button, to turn off, press the C.C.OFF button.
3.2 Confirm that both the turbo pump and the mechanical pump are turned off. If they are on, first turn off the turbo pump controller, and when the turbo pump speed is near zero, turn off the turbo pump power, then shut down the mechanical pump (touchscreen PUMP-1 OFF).
3.3 Open the main valve on the nitrogen cylinder rack with four connected cylinders and adjust the pressure reducing valve to the appropriate pressure (less than 0.1MPa), then start venting by opening the vent valve (touchscreen VENT-1 ON); remove the screws from the exposure chamber's sample entry and exit door; after venting is complete and the entry and exit door is opened, proceed with the exchange of the grating and the sample.
4. Replacement of Grating and Sample
4.1 If a grating mask needs to be replaced, the sample holder must be removed before replacing the grating. The grating mask must be fixed in place on the mask stage’s locating pins. After the grating has been replaced, confirm the grating's position again through the rear observation window.
4.2 When replacing a sample, the sample should be placed in the middle of the sample holder, taking care not to obstruct the observation holes reserved on the sample holder.
4.3 After the sample holder is fixed on the mask sample stage, close the entry and exit doors of the exposure chamber (secure the flange with screws, but do not tighten the screws too much), close the vent valve (touchscreen VENT-1 OFF), open V12, and start the mechanical pump (touchscreen PUMP-1 ON). After 5 minutes, turn on the turbo pump controller (power switch button on the back), and after the controller has started, press the start/stop button on the lower right corner of the controller to initiate the turbo pump program (the green indicator light changes from flashing to steady), and use the left and right control buttons to select the controller display to show the actual speed (code 309).
4.4 Close the main valve and the pressure reducing valve on the nitrogen cylinder. When the turbo pump controller indicates a full speed of 820Hz, turn on the vacuum gauge (Gauge g8). Once the vacuum level reaches 5E-6 Torr, open valves V13 and V18. When the vacuum level is better than 1E-6 Torr, subsequent exposure operations can be performed.
5. Pre-Exposure Preparation
5.1 When the vacuum gauge indicates that the vacuum level is better than 1E-6 Torr, move the sample stage to the position of the observation hole to observe the vacuum condition, ensuring that it continues to be better than 1E-6 Torr.
5.2 Close V12 and open V15, V16, V11, in the order of V15→V16→V11. Then, turn off the turbo pump controller (press the start/stop button on the lower right corner of the controller to initiate the shutdown of the turbo pump program, with the green indicator light changing from steady to flashing). Wait until the turbo pump controller indicates that the rotation speed is close to 0, then turn off the turbo pump controller (turn off the power switch button on the back), and finally, turn off the mechanical pump (on the touchscreen PUMP-1 OFF).
6. Exposure Operation
6.1 Open the CCD software (Andor SOLIS) and set the working temperature to -60℃. Set Shutter control to fully auto, with Close:Open(ms) = 50:50.
6.2 Switch the shutter control button to CCD control mode.
6.3 Lift the gold target (AuT) and FS3, and observe the light spot distribution at the mask through the CCD. Fine-tune the Angle Motion of M2 to even out the light spot (press the green VIDEO button to collect data, the red ABORT button to stop, then save as, naming it with the time, for example, 1402).
6.4 After the light spot has been adjusted to be even, switch the shutter control button back to cabinet control mode, lower the photodiode (PD) (position=0). Open the shutter, usually set to 500s, to collect light flux data. Open the automatic exposure system (refer to the specific steps of the automatic exposure program), confirm the F0 value, move away the photodiode (position=15000), and start automatic exposure.
6.5 After the exposure, lower the gold target (AuT) and FS3.
