OPERATION MANUAL Model 800 Nanoimprint Controller

Transcription

1 OPERATION MANUAL Model 800 Nanoimprint Controller 685 RIVER OAKS PARKWAY SAN JOSE, CA / , Rev. B 02/17/09

2 OAI Model 800 Nanolithosolution Nanoimprint Controller Operation Manual This manual covers the operation of the auto release nanoimprint system. The integrated nanoimprint system consists of the AR-NIM-100- OAI nanoimprint module, and the AR-IMC-100 nanoimprint controller. The system is controlled by a LCD display/control module connected to the nanoimprint controller. The following procedure illustrates the basic operation of the system. S1 1. Power on Push the power button on the AR-IMC-100 controller front panel to turn on the power of the whole system. When the system is powering on, an initialization screen S-1 will show on the LCD display. The system will execute an initialization process that takes about 1 minute. After the initialization is done, the LCD display will change to a new screen S-2, illustrated on the left. A group of setup parameters for the system are displayed on this screen. The user should check to make sure that they display recommended settings. See Setup of the system for details on how to modify the setup parameters. Pushing the Start the Imprint Process button will set the controller to nanoimprint mode. The LCD display will change to a new screen S-3. S2 2. Setup of the system There are parameters that must be checked and set before the start of the nanoimprint process, both for the nanoimprint system and OAI Series 800 aligner. This document assumes that the Model 800 has been turned on, and the UV light source has been ignited and stabilized. Please see the OAI Series 800 Operations Manual for further information. S3 For Series 800: A. Turn on the Series 800 aligner. Set the process to setting to Imprint (see section in the Series 800 operations manual). B. Set exposure time to 60 seconds. C. Proceed to the Level screen (see section in the Series 800 operations manual). D. Install the imprint chuck onto the Series 800 chuck holder using the 2 thumb screws to lock it in place. E. At this point, the aligner is configured for imprint. Proceed to the detailed description of the imprint procedure below. Manual PN: , Rev: B MANUAL MDL 800MBA NANOIMPR CNTRLR OPER 2 of 16

3 For ARIMC100: Press the Setup button on the LCD display to enter the Setup screen. Set parameters by touching the appropriate number, entering the value on the keypad, and pressing ENT. The new values will remain saved in the program s memory even after the system is powered off. Pushing Return will return to the nanoimprint control screen. Recommended settings are listed below: Parameter Setting Description Ps 28 Inflatable seal pressure [psi] Pi 1 Imprint pressure [psi] Pi ramp 0 Imprint pressure ramp-up time [s] T1 120 Wafer/mold gap vacuum pump down time [s] T2 2 Wait time before seal inflation [s] T3 60 Minimum wait time for nanoimprint to settle before UV exposure [s] 3. Nanoimprint process Once the desired settings are programmed and the controller is set to nanoimprint mode, users can simply follow the onscreen instructions to execute the nanoimprint process. See Section 4 for detailed explanations of each step. 4. Details of nanoimprint steps: 4.1 Load Mold: displays a message prompting the user to load the imprint mold on the mask holder. After finishing this action, push Next. 4.2 Place Mask Holder: displays a message prompting the user to load the mask holder on the mask frame. After finishing this action, push Next. 4.3 Load Wafer: Slide the chuck out from underneath the mask, and place a wafer on the nanoimprint module. After finishing this action, push Next. Manual PN: , Rev: B MANUAL MDL 800MBA NANOIMPR CNTRLR OPER 3 of 16

4 4.4. Fix Wafer: nanoimprint controller will activate vacuum to hold the wafer. Check that the wafer is held securely without any leaks, slide the chuck back underneath the mask, then push Next. 4.5 Alignment: displays a message prompting the user to perform the wafer/mold alignment process. Press the LEVEL button on the Series 800 control screen. This will planarize the wafer with the mold. When the planarization process is complete, alignment can be performed with the wafer in contact with the mold. Push Next on the LCD display. 4.6 Imprinting: nanoimprint controller will start a sequence of actions to performance imprinting. The sequence is automatically controlled, and the total time is T1 + T2 + T3. During the process, the user should see the System vacuum decrease then increase again, and imprint pressure increase to the programmed setpoint. At the end of the process, the nanoimprint controller will proceed automatically to the Exposure step. 4.7 Exposure: once the Imprinting step is complete, the user is prompted to start UV exposure. Press the Cycle button on the Series 800 control screen to initiate the UV exposure. When the UV shutter closes, push Next. 4.8 Release: There are two steps in the release process. When the nanoimprint controller first enters the Release state, it will turn off the imprinting pressure and wafer/mold gap vacuum. Wait 10 seconds then press the UNLOAD button on the Series 800 control screen to lower the nanoimprint module to separate the wafer from the mold. Slide the chuck out from underneath the mold and push the Next button to release the vacuum hold on the wafer. A process complete message will be displayed, and the program will reset for the next imprint run. ARIMC100_OAI mdl 800 Operation Manual V133 Manual PN: , Rev: B MANUAL MDL 800MBA NANOIMPR CNTRLR OPER 4 of 16

5 Nanolithosolution Auto Release TM Imprint Process Guide These procedures cover all the steps necessary to perform a nanoimprint process using the AR-NIM-100-OAI nanoimprint module, the AR-IMC-100 nanoimprint controller, the OAI Series 800 aligner, and standard microfabrication protocols. The process outlined here is designed to translate positive micro- and nano- patterns on a 3D quartz mold to metal patterns on a wafer. EQUIPMENT AND MATERIALS AR-NIM-100-OAI nanoimprint module AR-IMC-100 nanoimprint controller Mold coating chamber Nitrogen glove box OAI Series 800 Mask Alignment and Exposure System RIE etcher Ebeam evaporator Acid wet bench Spin-coater Hot plate Tweezers 0.2 Um Teflon filters with polypropylene body Polypropylene syringes AR-UVP UV polymer (AR-UV) AR-ULP under layer polymer (AR-UL) Surfactant Photoresist Sulfuric acid Hydrogen peroxide Acetone Methanol Isopropanol DI water Manual PN: , Rev: B MANUAL MDL 800MBA NANOIMPR CNTRLR OPER 5 of 16

6 PROCESS OVERVIEW The following flow diagram illustrates the high level process overview of transferring nanoimprint mold patterns to a silicon wafer. PROCESS FLOW TARGET FILM THICKNESS AR-UL nominal = 95nm, Range = 40nm to 110nm, thinner for better resolution AR-UV nominal = 70nm, Range = mold depth + 10nm. Mold depth nominal = 60 nm Metal nominal = 20nm, Range = 5nm to 30nm, thinner for better resolution Manual PN: , Rev: B MANUAL MDL 800MBA NANOIMPR CNTRLR OPER 6 of 16

7 DETAIL PROCESS RECOMMENDATION The following process is a recommendation for a typical microfabrication facility setting. User may optimize the parameters according to their equipment. 1 Wafer Cleaning 2 Spin coat ARUL polymer 3 Hard bake ARUL polymer film Manual PN: , Rev: B MANUAL MDL 800MBA NANOIMPR CNTRLR OPER 7 of 16

8 4. Spin coat AR-UV polymer 5. Imprinting Refer to Nanoimprint Controller Operation Manual. Typical settings on imprint controller T1: time between Pressure Seal to Imprint in seconds (default 120 sec) T2: time between Vacuum Gap to Pressure Seal in seconds (default 2 sec). T3: not used T4: minimum time for imprint in seconds (default 60 sec). 6. AR-UV polymer film etch 7. AR-UL polymer film etch Manual PN: , Rev: B MANUAL MDL 800MBA NANOIMPR CNTRLR OPER 8 of 16

9 8. Metal deposition 9. Metal liftoff Manual PN: , Rev: B MANUAL MDL 800MBA NANOIMPR CNTRLR OPER 9 of 16

10 PROCESS DEVELOPMENT GUIDE This section is a set of guides for new users to optimize processes on their own equipment. One of the critical factors in the yield of nanoimprint lithography is thin film processing. We recommend that new users first test and optimize etching and deposition of the related thin films. 1. AR-UL polymer film etch test The follow flow chart illustrates a process used to fine tune the AR-UL polymer film etch rate. Manual PN: , Rev: B MANUAL MDL 800MBA NANOIMPR CNTRLR OPER 10 of 16

11 AR-UV polymer film etch rate test The follow flow chart illustrates a process used to fine tune the AR-UV polymer film etch rate. Manual PN: , Rev: B MANUAL MDL 800MBA NANOIMPR CNTRLR OPER 11 of 16

12 2. Pattern transfer test In this test, the user would transfer the imprinted nano patterns on a ARUV polymer film to metal nano patterns on the silicon wafer. One can obtain test wafers from Nanolithosolution for this test. Manual PN: , Rev: B MANUAL MDL 800MBA NANOIMPR CNTRLR OPER 12 of 16

13 NANOMOLD FABRICATION Nanoimprint mold fabrication starts with a silicon master mold and an Auto Release TM quartz mold blank plate AR-MO-05. The silicon master mold is typical fabricated through an ebeam lithography process. Its pattern depth ranges from 50 nm to 100nm, depends on the feature size and density. A typical value to target is 75nm. For higher density and smaller feature sizes (40nm or less), it is recommended to reduce the pattern depth for typical RIE equipment. AR- MO-05 mold blank plate has prefabricated spacers and a silicon nitride thin film on one side of the plate. The spacers cover the wafer outside a 2 circular area, so the imprintable surface area is 2 diameter at the center of the wafer. The making of a working quartz mold is illustrated in the following flow diagram. Each of the process steps is documented in the earlier sections. Manual PN: , Rev: B MANUAL MDL 800MBA NANOIMPR CNTRLR OPER 13 of 16

14 PROCESS FOR MOLD TREATMENT LIQUID TREATMENT Treatment of the mold surface must be performed (either by the liquid or vapor method) to ensure clean release of the substrate from the mold after UV curing of the resist. This process forms a surfactant monolayer on the mold to lower its surface energy. The recommended surfactant is (tridecafluoro-1,1,2,2-tetrahydrooctyl) trichlorosilane (F13-TCS for short). 1. Mold cleaning Clean the mold in piranha solution (1 part H2O2 to 3 parts H2SO4) for 10 min. Use a freshly mixed solution, do not apply additional heat. If necessary, use O2 RIE to clean the mold. 2. Mold treating A. In a nitrogen glove box, immerse the mold in 0.5% surfactant solution (1 ml surfactant to 200 ml heptane) at room temperature for 2 minutes. B. Rinse the mold in 100 ml heptane at room temperature for 20 minutes to remove the unreacted surfactant. C. Rinse the mold by acetone, methanol and isopropanol. D. Bake the mold in an oven at 100 C for 40 minutes to form a more highly networked and highly bonded film. Manual PN: , Rev: B MANUAL MDL 800MBA NANOIMPR CNTRLR OPER 14 of 16

15 VAPOR TREATMENT 1. Immerse patterned borofloat mold in fresh piranha solution (3:1 H2SO4:H2O2) for 10 min, or O2 RIE to clean the plate (depends on the plate cleanliness). 2. Rinse mold under DI water for 1 min, and blowdry with N2. 3. Perform 5minute evaporation bake on hot plate at 150 C. 4. Vent mold coating chamber and place mold inside. 5. Pump chamber down to base pressure (~40 mtorr). 6. Close vacuum valve to isolate chamber from the pump. 7. Open surfactant valve until pressure reaches 300 mtorr, then close the valve. 8. Wait 10 minutes. 9. Open vacuum valve to pump chamber down to base pressure, then close the valve. 10. Carefully open water valve to bring chamber pressure up to 800 mtorr, then close the valve. 11. Wait 10 minutes. 12. Repeat steps 5-11 two more times for a total of three cycles. 13. Vent the chamber with N2 and remove the mold. 14. Optional step: sonicate the mold in HFE-7100 (3M Novec) for 1 min, then blow-dry. Manual PN: , Rev: B MANUAL MDL 800MBA NANOIMPR CNTRLR OPER 15 of 16

16 Procedure for Fabricating TEMP Imprint Quartz Mold This is a process for making a mold with quartz substrate, without doing the transfer etch step. Instead of etching into the substrate, the cured AR-UVP layer is used as the functional imprinting layer. Therefore the polarity of the quick mold will be opposite from the master mold. This type of mold is not quite as robust as the normal kind; however, at any time it can be immersed in acetone to strip the resist off, and the quartz plate can be reused. 1 Start with a mold blank plate (part# AR-MO-05). 2 Spin-coat plate with AR-ULP at 4000 rpm for 45 sec 3 Bake on hot plate at 180 C, 90 sec 4 Spincoat plate with AR-UVP at 2000 rpm for 7 sec 5 Imprint plate using Si master mold. Pi = 1 psi, Ps = 28 psi, T1 = 300 sec, T2 = 5 sec, T3 = 120 sec, cure at 20 mw/cm 2 for 2 min 6 Oxidize the surface of the cured resist: treat plate in RIE chamber with O2 50 sccm, 50 mtorr, 50 W, 20 sec. 7 Perform the release layer treatment 8 Use the quick mold for imprints in the same way as a regular mold Manual PN: , Rev: B MANUAL MDL 800MBA NANOIMPR CNTRLR OPER 16 of 16